perf sched replay: Realloc the memory of pid_to_task stepwise to adapt to the different pid_max configurations

Although the memory of pid_to_task can be allocated via calloc according
to the value of /proc/sys/kernel/pid_max, it cannot handle the case when
pid_max is changed after 'perf sched record' has created its perf.data.

If the new pid_max configured in 'perf sched replay' is smaller than the
old pid_max configured in 'perf sched record', then it will cause the
assertion failure problem.

To solve this problem, we realloc the memory of pid_to_task stepwise
once the passed-in pid parameter in register_pid is larger than the
current pid_max.

Example:

Test environment: x86_64 with 160 cores

 $ cat /proc/sys/kernel/pid_max
 163840
 $ perf sched record ls
 $ echo 5000 > /proc/sys/kernel/pid_max
 $ cat /proc/sys/kernel/pid_max
 5000

Before this patch:

 $ perf sched replay
 run measurement overhead: 221 nsecs
 sleep measurement overhead: 55356 nsecs
 the run test took 1000011 nsecs
 the sleep test took 1060940 nsecs
 perf: builtin-sched.c:337: register_pid: Assertion `!(pid >= (unsigned
 long)pid_max)' failed.
 Aborted

After this patch:

 $ perf sched replay
 run measurement overhead: 221 nsecs
 sleep measurement overhead: 55611 nsecs
 the run test took 1000026 nsecs
 the sleep test took 1060486 nsecs
 nr_run_events:        10
 nr_sleep_events:      1562
 nr_wakeup_events:     5
 task      0 (                  :1:         1), nr_events: 1
 task      1 (                  :2:         2), nr_events: 1
 task      2 (                  :3:         3), nr_events: 1
 task      3 (                  :5:         5), nr_events: 1
 ...
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427809596-29559-5-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

perf sched replay: Alloc the memory of pid_to_task dynamically to adapt to the unexpected change of pid_max

The current memory allocation of struct task_desc *pid_to_task[MAX_PID]
is in a permanent and preset way, and it has two problems:

Problem 1: If the pid_max, which is the max number of pids in the
system, is much smaller than MAX_PID (1024*1000), then it causes a waste
of stack memory. This may happen in the case where the number of cpu
cores is much smaller than 1000.

Problem 2: If the pid_max is changed from the default value to a value
larger than MAX_PID, then it will cause assertion failure problem. The
maximum value of pid_max can be set to pid_max_max (see pidmap_init
defined in kernel/pid.c), which equals to PID_MAX_LIMIT. In x86_64,
PID_MAX_LIMIT is 4*1024*1024 (defined in include/linux/threads.h). This
value is much larger than MAX_PID, and will take up 32768 Kbytes
(4*1024*1024*8/1024) for memory allocation of pid_to_task, which is much
larger than the default 8192 Kbytes of the stack size of calling
process.

Due to these two problems, we use calloc to allocate the memory of
pid_to_task dynamically.

Example:

Test environment: x86_64 with 160 cores

 $ cat /proc/sys/kernel/pid_max
 163840
 $ echo 1025000 > /proc/sys/kernel/pid_max
 $ cat /proc/sys/kernel/pid_max
 1025000

Run some applications until the pid of some process is greater than
the value of MAX_PID (1024*1000).

Before this patch:

 $ perf sched replay
 run measurement overhead: 221 nsecs
 sleep measurement overhead: 55480 nsecs
 the run test took 1000008 nsecs
 the sleep test took 1063151 nsecs
 perf: builtin-sched.c:330: register_pid: Assertion `!(pid >= 1024000)'
 failed.
 Aborted

After this patch:

 $ perf sched replay
 run measurement overhead: 221 nsecs
 sleep measurement overhead: 55435 nsecs
 the run test took 1000004 nsecs
 the sleep test took 1059312 nsecs
 nr_run_events:        10
 nr_sleep_events:      1562
 nr_wakeup_events:     5
 task      0 (                  :1:         1), nr_events: 1
 task      1 (                  :2:         2), nr_events: 1
 task      2 (                  :3:         3), nr_events: 1
 task      3 (                  :5:         5), nr_events: 1
 ...
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427809596-29559-4-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Current MAX_PID is only 65536, which will cause assertion failure problem
when CPU cores are more than 64 in x86_64.

This is because the pid_max value in x86_64 is at least
PIDS_PER_CPU_DEFAULT * num_possible_cpus() (see function pidmap_init
defined in kernel/pid.c), where PIDS_PER_CPU_DEFAULT is 1024 (defined in
include/linux/threads.h).

Thus for MAX_PID = 65536, the correspoinding CPU cores are
65536/1024=64.  This is obviously not enough at all for x86_64, and will
cause an assertion failure problem due to BUG_ON(pid >= MAX_PID) in the
codes.

We increase MAX_PID value from 65536 to 1024*1000, which can be used in
x86_64 with 1000 cores.

This number is finally decided according to the limitation of stack size
of calling process.

Use 'ulimit -a', the result shows the stack size of any process is 8192
Kbytes, which is defined in include/uapi/linux/resource.h (#define
_STK_LIM (8*1024*1024)).

Thus we choose a large enough value for MAX_PID, and make it satisfy to
the limitation of the stack size, i.e., making the perf process take up
a memory space just smaller than 8192 Kbytes.

We have calculated and tested that 1024*1000 is OK for MAX_PID.

This means perf sched replay can now be used with at most 1000 cores in
x86_64 without any assertion failure problem.

Example:

Test environment: x86_64 with 160 cores

 $ cat /proc/sys/kernel/pid_max
 163840

Before this patch:

 $ perf sched replay
 run measurement overhead: 240 nsecs
 sleep measurement overhead: 55379 nsecs
 the run test took 1000004 nsecs
 the sleep test took 1059424 nsecs
 perf: builtin-sched.c:330: register_pid: Assertion `!(pid >= 65536)'
 failed.
 Aborted

After this patch:

 $ perf sched replay
 run measurement overhead: 221 nsecs
 sleep measurement overhead: 55397 nsecs
 the run test took 999920 nsecs
 the sleep test took 1053313 nsecs
 nr_run_events:        10
 nr_sleep_events:      1562
 nr_wakeup_events:     5
 task      0 (                  :1:         1), nr_events: 1
 task      1 (                  :2:         2), nr_events: 1
 task      2 (                  :3:         3), nr_events: 1
 task      3 (                  :5:         5), nr_events: 1
 ...
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427809596-29559-3-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

There is no struct task_task at all, thus it is a typo error in the old
commits, now fix it to what it should be in order to avoid unnecessary
misunderstanding.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427809596-29559-2-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Currently the perf kmem does not respect -i option.

Initializing the file.path properly after options get parsed.
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1428298576-9785-2-git-send-email-namhyung@kernel.orgSigned-off-by: NNamhyung Kim <namhyung@kernel.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Currently it ignores operator priority and just sets processed args as a
right operand.  But it could result in priority inversion in case that
the right operand is also a operator arg and its priority is lower.

For example, following print format is from new kmem events.

  "page=%p", REC->pfn != -1UL ? (((struct page *)(0xffffea0000000000UL)) + (REC->pfn)) : ((void *)0)

But this was treated as below:

  REC->pfn != ((null - 1UL) ? ((struct page *)0xffffea0000000000UL + REC->pfn) : (void *) 0)

In this case, the right arg was '?' operator which has lower priority.
But it just sets the whole arg so making the output confusing - page was
always 0 or 1 since that's the result of logical operation.

With this patch, it can handle it properly like following:

  ((REC->pfn != (null - 1UL)) ? ((struct page *)0xffffea0000000000UL + REC->pfn) : (void *) 0)
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1428298576-9785-10-git-send-email-namhyung@kernel.org
[ Replaced 'swap' with 'rotate' in a comment as requested by Steve and agreed by Namhyung ]
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

This patch add checks in places where map__kmap is used to get kmaps
from struct kmap.

Error messages are added at map__kmap to warn invalid accessing of kmap
(for the case of !map->dso->kernel, kmap(map) does not exists at all).

Also, introduces map__kmaps() to warn uninitialized kmaps.
Reviewed-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Cc: pi3orama@163.com
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/r/1428394966-131044-2-git-send-email-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

perf_evlist__mmap_consume() uses perf_mmap__empty() to judge whether
perf_mmap is empty and can be released. But the result is inverted so
fix it.
Signed-off-by: NHe Kuang <hekuang@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1428399071-7141-1-git-send-email-hekuang@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

  - Support unnamed union/structure members data collection in 'perf probe'. (Masami Hiramatsu)

  - Support missing -f to override perf.data file ownership. (Yunlong Song)

Infrastructure changes:

  - No need to lookup thread twice when processing samples in 'perf script'. (Arnaldo Carvalho de Melo)

  - No need to pass thread twice to the scripting callbacks. (Arnaldo Carvalho de Melo)

  - No need to pass thread twice to the db-export facility. (Arnaldo Carvalho de Melo)
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Enable perf data convert to use perf.data when it is not owned by
current user or root.

Example:

 # perf record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 28260 Apr  2 17:35 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf data convert --to-ctf=./ctf-data/
 File perf.data not owned by current user or root (use -f to override)
 # perf data convert --to-ctf=./ctf-data/ -f
   Error: unknown switch `f'

  usage: perf data convert [<options>]

     -v, --verbose         be more verbose
     -i, --input <file>    input file name
         --to-ctf ...      Convert to CTF format

After this patch:

 # perf data convert --to-ctf=./ctf-data/
 File perf.data not owned by current user or root (use -f to override)
 # perf data convert --to-ctf=./ctf-data/ -f
 # ls ctf-data/
 metadata  perf_stream_0

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-11-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf trace to use perf.data when it is not owned by current user
or root.

Example:

 # perf trace record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 4153101 Apr  2 15:28 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf trace -i perf.data
 File perf.data not owned by current user or root (use -f to override)
 # perf trace -i perf.data -f
   Error: unknown switch `f'

  usage: perf trace [<options>] [<command>]
     or: perf trace [<options>] -- <command> [<options>]
     or: perf trace record [<options>] [<command>]
     or: perf trace record [<options>] -- <command> [<options>]

         --event <event>   event selector. use 'perf list' to list
 						  available events
         --comm            show the thread COMM next to its id
         --tool_stats      show tool stats
     -e, --expr <expr>     list of events to trace
     -o, --output <file>   output file name
     -i, --input <file>    Analyze events in file
     -p, --pid <pid>       trace events on existing process id
     -t, --tid <tid>       trace events on existing thread id
         --filter-pids <float>
  ...

As shown above, the -f option does not work at all.

After this patch:

 # perf trace -i perf.data
 File perf.data not owned by current user or root (use -f to override)
 # perf trace -i perf.data -f
 0.056 ( 0.002 ms): ls/47325 brk(                                 ...
 0.108 ( 0.018 ms): ls/47325 mmap(len: 4096, prot: READ|WRITE,    ...
 0.145 ( 0.013 ms): ls/47325 access(filename: 0x7f31259a0eb0,     ...
 0.172 ( 0.008 ms): ls/47325 open(filename: 0x7fffeb9a0d00,       ...
 0.180 ( 0.004 ms): ls/47325 stat(filename: 0x7fffeb9a0d00,       ...
 0.185 ( 0.004 ms): ls/47325 open(filename: 0x7fffeb9a0d00,       ...
 0.189 ( 0.003 ms): ls/47325 stat(filename: 0x7fffeb9a0d00,       ...
 0.195 ( 0.004 ms): ls/47325 open(filename: 0x7fffeb9a0d00,       ...
 0.199 ( 0.002 ms): ls/47325 stat(filename: 0x7fffeb9a0d00,       ...
 0.205 ( 0.004 ms): ls/47325 open(filename: 0x7fffeb9a0d00,       ...
 0.211 ( 0.004 ms): ls/47325 stat(filename: 0x7fffeb9a0d00,       ...
 0.220 ( 0.007 ms): ls/47325 open(filename: 0x7f312599e8ff,       ...
 ...
 ...

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-10-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf timechart to use perf.data when it is not owned by current
user or root.

Example:

 # perf timechart record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 5471744 Apr  2 15:15 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf timechart
 File perf.data not owned by current user or root (use -f to override)
 # perf timechart -f
   Error: unknown switch `f'

  usage: perf timechart [<options>] {record}

     -i, --input <file>    input file name
     -o, --output <file>   output file name
     -w, --width <n>       page width
         --highlight <duration or task name>
                           highlight tasks. Pass duration in ns or process name.
     -P, --power-only      output power data only
     -T, --tasks-only      output processes data only
     -p, --process <process>
                           process selector. Pass a pid or process name.
         --symfs <directory>
                           Look for files with symbols relative to this directory
     -n, --proc-num <n>    min. number of tasks to print
     -t, --topology        sort CPUs according to topology
         --io-skip-eagain  skip EAGAIN errors
         --io-min-time <time>
                           all IO faster than min-time will visually appear longer
         --io-merge-dist <time>
                           merge events that are merge-dist us apart

As shown above, the -f option does not work at all.

After this patch:

 # perf timechart
 File perf.data not owned by current user or root (use -f to override)
 # perf timechart -f
 Written 0.0 seconds of trace to output.svg.
 # cat output.svg
 <?xml version="1.0" standalone="no"?>
 <!DOCTYPE svg SYSTEM "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
 <svg width="1000" height="10110" version="1.1" xmlns="http://www.w3.org/2000/svg">
 <defs>
   <style type="text/css">
     <![CDATA[
       rect          { stroke-width: 1; }
 ...
 ...

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-9-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf script to use perf.data when it is not owned by current user
or root. Change the short option name of --fields to -F to avoid confusion
with --force.

Example:

 # perf record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 28360 Apr  2 14:53 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf script
 File perf.data not owned by current user or root (use -f to override)
 # perf script -f
   Error: switch `f' requires a value

  usage: perf script [<options>]
     or: perf script [<options>] record <script> [<record-options>] <command>
     or: perf script [<options>] report <script> [script-args]
     or: perf script [<options>] <script> [<record-options>] <command>
     or: perf script [<options>] <top-script> [script-args]

     -f, --fields <str>    comma separated output fields prepend with
     'type:'. Valid types: hw,sw,trace,raw. Fields:
     comm,tid,pid,time,cpu,event,trace,ip,sym,dso,addr,symoff,period

As shown above, the -f option does not work at all. And -f is already
taken up by --fields, which makes --force confused, so change the short
option name of --fields to -F like what other perf commands do (e.g.
perf report -F) and use -f as the short option name of --force.

After this patch:

 # perf script
 File perf.data not owned by current user or root (use -f to override)
 # perf script -f
 :41298 41298 2590086.564226:          1 cycles:  ffffffff8103efc6
 native_write_msr_safe ([kernel.kallsyms])
 :41298 41298 2590086.564244:          1 cycles:  ffffffff8103efc6
 native_write_msr_safe ([kernel.kallsyms])
 :41298 41298 2590086.564249:          7 cycles:  ffffffff8103efc6
 native_write_msr_safe ([kernel.kallsyms])
 :41298 41298 2590086.564255:        176 cycles:  ffffffff8103efc6
 native_write_msr_safe ([kernel.kallsyms])
     ls 41298 2590086.567346:       4059 cycles:  ffffffff8105a592
     raise_softirq ([kernel.kallsyms])
     ls 41298 2590086.567353:       3717 cycles:  ffffffff8105a592
     raise_softirq ([kernel.kallsyms])
     ls 41298 2590086.567358:      63058 cycles:  ffffffff8105a592
     raise_softirq ([kernel.kallsyms])
     ls 41298 2590086.567448:    1706255 cycles:            406ae0
     [unknown] (/usr/bin/ls)

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-8-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf mem to use perf.data when it is not owned by current user or
root.

Example:

 # perf mem -t load record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 16392 Apr  2 14:34 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf mem -D report
 File perf.data not owned by current user or root (use -f to override)
 # perf mem -D -f report
   Error: unknown switch `f'

  usage: perf mem [<options>] {record|report}

     -t, --type <type>     memory operations(load,store) Default load,store
     -D, --dump-raw-samples
                           dump raw samples in ASCII
     -U, --hide-unresolved
                           Only display entries resolved to a symbol
     -i, --input <file>    input file name
     -C, --cpu <cpu>       list of cpus to profile
     -x, --field-separator <separator>
                           separator for columns, no spaces will be added
                           between columns '.' is reserved.

As shown above, the -f option does not work at all.

After this patch:

 # perf mem -D report
 File perf.data not owned by current user or root (use -f to override)
 # perf mem -D -f report
 # PID, TID, IP, ADDR, LOCAL WEIGHT, DSRC, SYMBOL
 39095 39095 0xffffffff81127e40 0x016ffff887f45148338 8 0x68100142
 /proc/kcore:perf_event_aux
 39095 39095 0xffffffff8100a3fe 0xffff89007f8cb7d0 6 0x68100142
 /proc/kcore:native_sched_clock
 39095 39095 0xffffffff81309139 0xffff88bf44c9ded8 6 0x68100142
 /proc/kcore:acpi_map_lookup
 39095 39095 0xffffffff810f8c4c 0xffff89007f8ccd88 6 0x68100142
 /proc/kcore:rcu_nmi_exit
 39095 39095 0xffffffff81136346 0xffff88fea995dd50 6 0x68100142
 /proc/kcore:unlock_page
 39095 39095 0xffffffff812a64a2 0xffff88fea995dcc8 6 0x68100142
 /proc/kcore:half_md4_transform
 39095 39095 0x7f0cf877c7e9 0x25dfb94 6 0x68100142
 /lib64/libc-2.19.so:__readdir64
 39095 39095 0x7f0cf87575a3 0x7f0cf9163731 6 0x68100142
 /lib64/libc-2.19.so:__strcoll_l
 39095 39095 0xffffffff8116910e 0xffffea01c1bfbd50 23 0x68100242
 /proc/kcore:page_remove_rmap

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-7-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf lock to use perf.data when it is not owned by current user
or root.

Example:

 # perf lock record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 4880686 Apr  2 14:14 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf lock report
 File perf.data not owned by current user or root (use -f to override)
 Initializing perf session failed
 # perf lock report -f
   Error: unknown switch `f'

  usage: perf lock report [<options>]

     -k, --key <acquired>  key for sorting (acquired / contended /
     avg_wait / wait_total / wait_max / wait_min)

As shown above, the -f option does not work at all.

After this patch:

 # perf lock report
 File perf.data not owned by current user or root (use -f to override)
 Initializing perf session failed
 # perf lock report -f
                Name   acquired  contended   avg wait (ns) total wait (ns) ...

 &ldata->output_l...        128          0               0               0 ...
          &ctx->lock        114          0               0               0 ...
         &p->pi_lock        112          0               0               0 ...
 &(&pool->lock)->...        112          0               0               0 ...
 &(&dentry->d_loc...         70          0               0               0 ...
 &(&newf->file_lo...         62          0               0               0 ...
 &(&fs->lock)->rl...         43          0               0               0 ...
 ...

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-6-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf kvm to use perf.data.guest when it is not owned by current
user or root.

Example:

 # perf kvm stat record ls
 # chown Yunlong.Song:Yunlong.Song perf.data.guest
 # ls -al perf.data.guest
 -rw------- 1 Yunlong.Song Yunlong.Song 4128937 Apr  2 11:05 perf.data.guest
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf kvm stat report
 File perf.data.guest not owned by current user or root (use -f to override)
 Initializing perf session failed
 # perf kvm stat report -f
   Error: unknown switch `f'

  usage: perf kvm stat report [<options>]

         --event <report event>
                           event for reporting: vmexit, mmio (x86 only),
                           ioport (x86 only)
         --vcpu <n>        vcpu id to report
     -k, --key <sort-key>  key for sorting: sample(sort by samples
 						   number) time (sort by avg time)
     -p, --pid <pid>       analyze events only for given process id(s)

As shown above, the -f option does not work at all.

After this patch:

 # perf kvm stat report
 File perf.data.guest not owned by current user or root (use -f to override)
 Initializing perf session failed
 # perf kvm stat report -f
 Analyze events for all VMs, all VCPUs:

   VM-EXIT    Samples  Samples%     Time%    Min Time    Max Time   Avg time

 Total Samples:0, Total events handled time:0.00us.

As shown above, the -f option really works now. Since we have not
launched any KVM related process, the result shows 0 sample here.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-5-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf kmem to use perf.data when it is not owned by current user
or root.

Example:

 # perf kmem record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 5315665 Apr  2 10:54 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf kmem stat
 File perf.data not owned by current user or root (use -f to override)
 # perf kmem stat -f
   Error: unknown switch `f'

  usage: perf kmem [<options>] {record|stat}

     -i, --input <file>    input file name
     -v, --verbose         be more verbose (show symbol address, etc)
         --caller          show per-callsite statistics
         --alloc           show per-allocation statistics
     -s, --sort <key[,key2...]>
                           sort by keys: ptr, call_site, bytes, hit,
                           pingpong, frag
     -l, --line <num>      show n lines
         --raw-ip          show raw ip instead of symbol

As shown above, the -f option does not work at all.

After this patch:

 # perf kmem stat
 File perf.data not owned by current user or root (use -f to override)
 # perf kmem stat -f
 SUMMARY
 =======
 Total bytes requested: 437599
 Total bytes allocated: 615472
 Total bytes wasted on internal fragmentation: 177873
 Internal fragmentation: 28.900259%
 Cross CPU allocations: 6/1192

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-4-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf inject to use perf.data when it is not owned by current user
or root.

Example:

 # perf record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 28260 Apr  2 10:37 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf inject -v -b -i perf.data -o perf.data.new
 File perf.data not owned by current user or root (use -f to override)
 # perf inject -v -b -i perf.data -o perf.data.new -f
   Error: unknown switch `f'

  usage: perf inject [<options>]

     -b, --build-ids       Inject build-ids into the output stream
     -i, --input <file>    input file name
     -o, --output <file>   output file name
     -s, --sched-stat      Merge sched-stat and sched-switch for getting
     events where and how long tasks slept
     -v, --verbose         be more verbose (show build ids, etc)
         --kallsyms <file>
                           kallsyms pathname

As shown above, the -f option does not work at all.

After this patch:

 # perf inject -v -b -i perf.data -o perf.data.new
 File perf.data not owned by current user or root (use -f to override)
 # perf inject -v -b -i perf.data -o perf.data.new -f
 build id event received for [kernel.kallsyms]:
 f6dcb66d8b98f1c0d9eb87bf043444b69f91d30c
 symsrc__init: cannot get elf header.
 Looking at the vmlinux_path (7 entries long)
 Using /proc/kcore for kernel object code
 Using /proc/kallsyms for symbols

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-3-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Enable perf evlist to use perf.data when it is not owned by current user
or root.

Example:

 # perf record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 28260 Apr  2 10:18 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf evlist
 File perf.data not owned by current user or root (use -f to override)
 # perf evlist -f
   Error: unknown switch `f'

  usage: perf evlist [<options>]

     -i, --input <file>    Input file name
     -F, --freq            Show the sample frequency
     -v, --verbose         Show all event attr details
     -g, --group           Show event group information

As shown above, the -f option does not work at all.

After this patch:

 # perf evlist
 File perf.data not owned by current user or root (use -f to override)
 # perf evlist -f
 cycles

As shown above, the -f option really works now.
Signed-off-by: NYunlong Song <yunlong.song@huawei.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-2-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Fix 'perf probe' to track down unnamed union/structure members.

perf probe did not track down the tree of unnamed union/structure
members, since it just failed to find given "name" in a parent
structure/union.  To solve this issue, I've introduced 2 changes.

- Fix die_find_member() to track down the type-DIE if it is
  unnamed, and if it contains the specified member, returns the
  unnamed member.
  (note that we don't return found member, since unnamed member
   has the offset in the parent structure)
- Fix convert_variable_fields() to track down the unnamed union/
  structure (one-by-one).

With this patch, perf probe can access unnamed fields:
  -----
  #./perf probe -nfx ./perf lock__delete ops 'locked_ops=ops->locked.ops'
  Added new event:
    probe_perf:lock__delete (on lock__delete in /home/mhiramat/ksrc/linux-3/tools/perf/perf with ops locked_ops=ops->locked.ops)

  You can now use it in all perf tools, such as:

          perf record -e probe_perf:lock__delete -aR sleep 1
  -----
Reported-by: NArnaldo Carvalho de Melo <acme@kernel.org>
Report-Link: https://lkml.org/lkml/2015/3/5/431Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150402073312.14482.37942.stgit@localhost.localdomainSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

As it comes from address_location->thread, that is already stored as
export_sample->al, where the thread can be obtained.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20150402141542.GA9630@kernel.org
Link: http://lkml.kernel.org/n/tip-bzotbl4epoztw0jd6sm2stpf@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

As it is available via another parameter, address_location->thread.
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: lkml.kernel.org/r/551D08F8.3040706@intel.com
Link: http://lkml.kernel.org/n/tip-6dbn0tcm9hyv92g7h3zj2dbt@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

It is already in the addr_location, so remove the redundant 'thread'
parameter from the callback signatures.
Acked-by: NJiri Olsa <jolsa@redhat.com>
Acked-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1427906210-10519-3-git-send-email-acme@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

We get the thread when we call perf_event__preprocess_sample(), no need
to do it before that.
Acked-by: NJiri Olsa <jolsa@redhat.com>
Acked-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1427906210-10519-2-git-send-email-acme@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

On a 32-bit build I got:

  arch/x86/kernel/cpu/perf_event_intel_pt.c:413:5: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
  arch/x86/kernel/cpu/perf_event_intel_bts.c:162:24: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]

Fix it. The code should probably be (re-)tested on 32-bit systems to make
sure all is fine.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kaixu Xia <kaixu.xia@linaro.org>
Cc: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: adrian.hunter@intel.com
Cc: kan.liang@intel.com
Cc: markus.t.metzger@intel.com
Cc: mathieu.poirier@linaro.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

perf with LBRs on has a tendency to rewrite the DEBUGCTL MSR with
the same value. Add a little optimization to skip the unnecessary
write.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1426871484-21285-2-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

The perf PMI currently does unnecessary MSR accesses when
LBRs are enabled. We use LBR freezing, or when in callstack
mode force the LBRs to only filter on ring 3.

So there is no need to disable the LBRs explicitely in the
PMI handler.

Also we always unnecessarily rewrite LBR_SELECT in the LBR
handler, even though it can never change.

 5)               |  /* write_msr: MSR_LBR_SELECT(1c8), value 0 */
 5)               |  /* read_msr: MSR_IA32_DEBUGCTLMSR(1d9), value 1801 */
 5)               |  /* write_msr: MSR_IA32_DEBUGCTLMSR(1d9), value 1801 */
 5)               |  /* write_msr: MSR_CORE_PERF_GLOBAL_CTRL(38f), value 70000000f */
 5)               |  /* write_msr: MSR_CORE_PERF_GLOBAL_CTRL(38f), value 0 */
 5)               |  /* write_msr: MSR_LBR_SELECT(1c8), value 0 */
 5)               |  /* read_msr: MSR_IA32_DEBUGCTLMSR(1d9), value 1801 */
 5)               |  /* write_msr: MSR_IA32_DEBUGCTLMSR(1d9), value 1801 */

This patch:

  - Avoids disabling already frozen LBRs unnecessarily in the PMI
  - Avoids changing LBR_SELECT in the PMI
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1426871484-21285-1-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Technically PEBS_ENABLED is only guaranteed to exist when we
detected PEBS. So add a check for this to the PMU dump function.
I don't think it can happen on a real CPU, but could in a VM.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1425059312-18217-4-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

LBRs and LBR freezing are controlled through the DEBUGCTL MSR. So
dump the state of DEBUGCTL too when dumping the PMU state.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1425059312-18217-3-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

The PMU reset code didn't quite keep up with newer PMU features.
Improve it a bit to really reset a modern PMU:

  - Clear all overflow status
  - Clear LBRs and freezing state
  - Disable fixed counters too
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1425059312-18217-2-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch disables the PMU HT bug when Hyperthreading (HT)
is disabled. We cannot do this test immediately when perf_events
is initialized. We need to wait until the topology information
is setup properly. As such, we register a later initcall, check
the topology and potentially disable the workaround. To do this,
we need to ensure there is no user of the PMU. At this point of
the boot, the only user is the NMI watchdog, thus we disable
it during the switch and re-enable it right after.

Having the workaround disabled when it is not needed provides
some benefits by limiting the overhead is time and space.
The workaround still ensures correct scheduling of the corrupting
memory events (0xd0, 0xd1, 0xd2) when HT is off. Those events
can only be measured on counters 0-3. Something else the current
kernel did not handle correctly.
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: bp@alien8.de
Cc: jolsa@redhat.com
Cc: kan.liang@intel.com
Cc: maria.n.dimakopoulou@gmail.com
Link: http://lkml.kernel.org/r/1416251225-17721-13-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch adds two new functions to enable/disable
the watchdog across all CPUs.

This will be used by the HT PMU bug workaround code to
disable/enable the NMI watchdog across quirk enablement.
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: bp@alien8.de
Cc: jolsa@redhat.com
Cc: kan.liang@intel.com
Cc: maria.n.dimakopoulou@gmail.com
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1416251225-17721-12-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

perf/x86/intel: Limit to half counters when the HT workaround is enabled, to avoid exclusive mode starvation

This patch limits the number of counters available to each CPU when
the HT bug workaround is enabled.

This is necessary to avoid situation of counter starvation. Such can
arise from configuration where one HT thread, HT0, is using all 4 counters
with corrupting events which require exclusion the the sibling HT, HT1.

In such case, HT1 would not be able to schedule any event until HT0
is done. To mitigate this problem, this patch artificially limits
the number of counters to 2.

That way, we can gurantee that at least 2 counters are not in exclusive
mode and therefore allow the sibling thread to schedule events of the
same type (system vs. per-thread). The 2 counters are not determined
in advance. We simply set the limit to two events per HT.

This helps mitigate starvation in case of events with specific counter
constraints such a PREC_DIST.

Note that this does not elimintate the starvation is all cases. But
it is better than not having it.

(Solution suggested by Peter Zjilstra.)
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: bp@alien8.de
Cc: jolsa@redhat.com
Cc: kan.liang@intel.com
Cc: maria.n.dimakopoulou@gmail.com
Link: http://lkml.kernel.org/r/1416251225-17721-11-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

With dynamic constraint, we need to restart from the static
constraints each time the intel_get_event_constraints() is called.
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NMaria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Cc: bp@alien8.de
Cc: jolsa@redhat.com
Cc: kan.liang@intel.com
Link: http://lkml.kernel.org/r/1416251225-17721-10-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch modifies the PEBS constraint tables for SNB/IVB/HSW
such that corrupting events supporting PEBS activate the HT
workaround.
Signed-off-by: NMaria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NStephane Eranian <eranian@google.com>
Cc: bp@alien8.de
Cc: jolsa@redhat.com
Cc: kan.liang@intel.com
Link: http://lkml.kernel.org/r/1416251225-17721-9-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patches activates the HT bug workaround for the
SNB/IVB/HSW processors. This covers non-PEBS mode.
Activation is done thru the constraint tables.

Both client and server processors needs this workaround.
Signed-off-by: NMaria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NStephane Eranian <eranian@google.com>
Cc: bp@alien8.de
Cc: jolsa@redhat.com
Cc: kan.liang@intel.com
Link: http://lkml.kernel.org/r/1416251225-17721-8-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch implements a software workaround for a HW erratum
on Intel SandyBridge, IvyBridge and Haswell processors
with Hyperthreading enabled. The errata are documented for
each processor in their respective specification update
documents:

  - SandyBridge: BJ122
  - IvyBridge: BV98
  - Haswell: HSD29

The bug causes silent counter corruption across hyperthreads only
when measuring certain memory events (0xd0, 0xd1, 0xd2, 0xd3).
Counters measuring those events may leak counts to the sibling
counter. For instance, counter 0, thread 0 measuring event 0xd0,
may leak to counter 0, thread 1, regardless of the event measured
there. The size of the leak is not predictible. It all depends on
the workload and the state of each sibling hyper-thread. The
corrupting events do undercount as a consequence of the leak. The
leak is compensated automatically only when the sibling counter measures
the exact same corrupting event AND the workload is on the two threads
is the same. Given, there is no way to guarantee this, a work-around
is necessary. Furthermore, there is a serious problem if the leaked count
is added to a low-occurrence event. In that case the corruption on
the low occurrence event can be very large, e.g., orders of magnitude.

There is no HW or FW workaround for this problem.

The bug is very easy to reproduce on a loaded system.
Here is an example on a Haswell client, where CPU0, CPU4
are siblings. We load the CPUs with a simple triad app
streaming large floating-point vector. We use 0x81d0
corrupting event (MEM_UOPS_RETIRED:ALL_LOADS) and
0x20cc (ROB_MISC_EVENTS:LBR_INSERTS). Given we are not
using the LBR, the 0x20cc event should be zero.

  $ taskset -c 0 triad &
  $ taskset -c 4 triad &
  $ perf stat -a -C 0 -e r81d0 sleep 100 &
  $ perf stat -a -C 4 -r20cc sleep 10
  Performance counter stats for 'system wide':
        139 277 291      r20cc
       10,000969126 seconds time elapsed

In this example, 0x81d0 and r20cc ar eusing sinling counters
on CPU0 and CPU4. 0x81d0 leaks into 0x20cc and corrupts it
from 0 to 139 millions occurrences.

This patch provides a software workaround to this problem by modifying the
way events are scheduled onto counters by the kernel. The patch forces
cross-thread mutual exclusion between counters in case a corrupting event
is measured by one of the hyper-threads. If thread 0, counter 0 is measuring
event 0xd0, then nothing can be measured on counter 0, thread 1. If no corrupting
event is measured on any hyper-thread, event scheduling proceeds as before.

The same example run with the workaround enabled, yield the correct answer:

  $ taskset -c 0 triad &
  $ taskset -c 4 triad &
  $ perf stat -a -C 0 -e r81d0 sleep 100 &
  $ perf stat -a -C 4 -r20cc sleep 10
  Performance counter stats for 'system wide':
        0 r20cc
       10,000969126 seconds time elapsed

The patch does provide correctness for all non-corrupting events. It does not
"repatriate" the leaked counts back to the leaking counter. This is planned
for a second patch series. This patch series makes this repatriation more
easy by guaranteeing the sibling counter is not measuring any useful event.

The patch introduces dynamic constraints for events. That means that events which
did not have constraints, i.e., could be measured on any counters, may now be
constrained to a subset of the counters depending on what is going on the sibling
thread. The algorithm is similar to a cache coherency protocol. We call it XSU
in reference to Exclusive, Shared, Unused, the 3 possible states of a PMU
counter.

As a consequence of the workaround, users may see an increased amount of event
multiplexing, even in situtations where there are fewer events than counters
measured on a CPU.

Patch has been tested on all three impacted processors. Note that when
HT is off, there is no corruption. However, the workaround is still enabled,
yet not costing too much. Adding a dynamic detection of HT on turned out to
be complex are requiring too much to code to be justified.

This patch addresses the issue when PEBS is not used. A subsequent patch
fixes the problem when PEBS is used.
Signed-off-by: NMaria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
[spinlock_t -> raw_spinlock_t]
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NStephane Eranian <eranian@google.com>
Cc: bp@alien8.de
Cc: jolsa@redhat.com
Cc: kan.liang@intel.com
Link: http://lkml.kernel.org/r/1416251225-17721-7-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch adds a new shared_regs style structure to the
per-cpu x86 state (cpuc). It is used to coordinate access
between counters which must be used with exclusion across
HyperThreads on Intel processors. This new struct is not
needed on each PMU, thus is is allocated on demand.
Signed-off-by: NMaria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
[peterz: spinlock_t -> raw_spinlock_t]
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NStephane Eranian <eranian@google.com>
Cc: bp@alien8.de
Cc: jolsa@redhat.com
Cc: kan.liang@intel.com
Link: http://lkml.kernel.org/r/1416251225-17721-6-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch adds an index parameter to the get_event_constraint()
x86_pmu callback. It is expected to represent the index of the
event in the cpuc->event_list[] array. When the callback is used
for fake_cpuc (evnet validation), then the index must be -1. The
motivation for passing the index is to use it to index into another
cpuc array.
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: bp@alien8.de
Cc: jolsa@redhat.com
Cc: kan.liang@intel.com
Cc: maria.n.dimakopoulou@gmail.com
Link: http://lkml.kernel.org/r/1416251225-17721-5-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch adds 3 new PMU model specific callbacks
during the event scheduling done by x86_schedule_events().

  ->start_scheduling():  invoked when entering the schedule routine.
  ->stop_scheduling():   invoked at the end of the schedule routine
  ->commit_scheduling(): invoked for each committed event

To be used optionally by model-specific code.
Signed-off-by: NMaria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NStephane Eranian <eranian@google.com>
Cc: bp@alien8.de
Cc: jolsa@redhat.com
Cc: kan.liang@intel.com
Link: http://lkml.kernel.org/r/1416251225-17721-4-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>