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  1. 29 4月, 2015 11 次提交
  3. 14 4月, 2015 4 次提交
  5. 13 4月, 2015 2 次提交
    • N
      perf kmem: Analyze page allocator events also · 0d68bc92
      由 Namhyung Kim 提交于 
      The perf kmem command records and analyze kernel memory allocation only
for SLAB objects.  This patch implement a simple page allocator analyzer
using kmem:mm_page_alloc and kmem:mm_page_free events.

It adds two new options of --slab and --page.  The --slab option is for
analyzing SLAB allocator and that's what perf kmem currently does.

The new --page option enables page allocator events and analyze kernel
memory usage in page unit.  Currently, 'stat --alloc' subcommand is
implemented only.

If none of these --slab nor --page is specified, --slab is implied.

First run 'perf kmem record' to generate a suitable perf.data file:

  # perf kmem record --page sleep 5

Then run 'perf kmem stat' to postprocess the perf.data file:

  # perf kmem stat --page --alloc --line 10

  -------------------------------------------------------------------------------
   PFN              | Total alloc (KB) | Hits     | Order | Mig.type | GFP flags
  -------------------------------------------------------------------------------
            4045014 |               16 |        1 |     2 |  RECLAIM |  00285250
            4143980 |               16 |        1 |     2 |  RECLAIM |  00285250
            3938658 |               16 |        1 |     2 |  RECLAIM |  00285250
            4045400 |               16 |        1 |     2 |  RECLAIM |  00285250
            3568708 |               16 |        1 |     2 |  RECLAIM |  00285250
            3729824 |               16 |        1 |     2 |  RECLAIM |  00285250
            3657210 |               16 |        1 |     2 |  RECLAIM |  00285250
            4120750 |               16 |        1 |     2 |  RECLAIM |  00285250
            3678850 |               16 |        1 |     2 |  RECLAIM |  00285250
            3693874 |               16 |        1 |     2 |  RECLAIM |  00285250
   ...              | ...              | ...      | ...   | ...      | ...
  -------------------------------------------------------------------------------

  SUMMARY (page allocator)
  ========================
  Total allocation requests     :           44,260   [          177,256 KB ]
  Total free requests           :              117   [              468 KB ]

  Total alloc+freed requests    :               49   [              196 KB ]
  Total alloc-only requests     :           44,211   [          177,060 KB ]
  Total free-only requests      :               68   [              272 KB ]

  Total allocation failures     :                0   [                0 KB ]

  Order     Unmovable   Reclaimable       Movable      Reserved  CMA/Isolated
  -----  ------------  ------------  ------------  ------------  ------------
      0            32             .        44,210             .             .
      1             .             .             .             .             .
      2             .            18             .             .             .
      3             .             .             .             .             .
      4             .             .             .             .             .
      5             .             .             .             .             .
      6             .             .             .             .             .
      7             .             .             .             .             .
      8             .             .             .             .             .
      9             .             .             .             .             .
     10             .             .             .             .             .
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
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/1428298576-9785-4-git-send-email-namhyung@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      0d68bc92
    • N
      tracing, mm: Record pfn instead of pointer to struct page · 9fdd8a87
      由 Namhyung Kim 提交于 
      The struct page is opaque for userspace tools, so it'd be better to save
pfn in order to identify page frames.

The textual output of $debugfs/tracing/trace file remains unchanged and
only raw (binary) data format is changed - but thanks to libtraceevent,
userspace tools which deal with the raw data (like perf and trace-cmd)
can parse the format easily.  So impact on the userspace will also be
minimal.
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Based-on-patch-by: NJoonsoo Kim <js1304@gmail.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.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/1428298576-9785-3-git-send-email-namhyung@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      9fdd8a87
  7. 12 4月, 2015 1 次提交
  9. 11 4月, 2015 1 次提交
    • I
      Merge tag 'perf-core-for-mingo' of... · 5dafd7cb
      由 Ingo Molnar 提交于 
      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:

New user visible features:

  - Support multiple probes on different binaries on the same command line (Masami Hiramatsu)

User visible changes:

  - Fix synthesizing fork_event.ppid for non-main thread (David Ahern)

  - Fix cross-endian analysis (David Ahern)

  - Fix segfault in 'perf buildid-list' when show DSOs with hits (He Kuang)

Infrastructure changes:

  - Fix type for references to data_head/tail (David Ahern)

  - Fix error path to do closedir() when synthesizing threads (Arnaldo Carvalho de Melo)
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      5dafd7cb
  11. 10 4月, 2015 7 次提交
  13. 08 4月, 2015 14 次提交
    • I
      Merge tag 'perf-core-for-mingo' of... · 51ab7155
      由 Ingo Molnar 提交于 
      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:

  - Teach 'perf record' about perf_event_attr.clockid (Peter Zijlstra)

  - Improve 'perf sched replay' on high CPU core count machines (Yunlong Song)

  - Consider PERF_RECORD_ events with cpumode == 0 in 'perf top', removing one
    cause of long term memory usage buildup, i.e. not processing PERF_RECORD_EXIT
    events (Arnaldo Carvalho de Melo)

  - Add 'I' event modifier for perf_event_attr.exclude_idle bit (Jiri Olsa)

  - Respect -i option 'in perf kmem' (Jiri Olsa)

Infrastructure changes:

  - Honor operator priority in libtraceevent (Namhyung Kim)

  - Merge all perf_event_attr print functions (Peter Zijlstra)

  - Check kmaps access to make code more robust (Wang Nan)

  - Fix inverted logic in perf_mmap__empty() (He Kuang)

  - Fix ARM 32 'perf probe' building error (Wang Nan)

  - Fix perf_event_attr tests (Jiri Olsa)
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      51ab7155
    • J
      perf tools: Add 'I' event modifier for exclude_idle bit · a1e12da4
      由 Jiri Olsa 提交于 
      Adding 'I' event modifier to have complete set of modifiers for
perf_event_attr:exclude_* bits.

Any event specified with 'I' modifier will have the
perf_event_attr:exclude_idle bit set.

  $ perf record -e cycles:I -vv ls 2>&1 | grep exclude_idle
  exclude_hv          0    exclude_idle        1

Adding automated tests.
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: William Cohen <wcohen@redhat.com>
Link: http://lkml.kernel.org/r/1428441919-23099-2-git-send-email-jolsa@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      a1e12da4
    • W
      perf report: Don't call map__kmap if map is NULL. · f6fcc143
      由 Wang Nan 提交于 
      report__warn_kptr_restrict() calls map__kmap(kernel_map) before checking
kernel_map againest NULL.

Which is dangerous, since map__kmap() will return a invalid and not NULL
address.

It will trigger a warning message in map__kmap() after the patch "perf:
kmaps: enforce usage of kmaps to protect futher bugs." was applied.

This patch fixes it by adding the missing checking.
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1428490772-135393-1-git-send-email-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      f6fcc143
    • J
      perf tests: Fix attr tests · 54a50f93
      由 Jiri Olsa 提交于 
      Following commit:
  1a594131 perf: Add wakeup watermark control to the AUX area

enlarged perf_event_attr, but did not updated attr tests.
Reported-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Kaixu Xia <kaixu.xia@linaro.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Markus T Metzger <markus.t.metzger@intel.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: http://lkml.kernel.org/n/20150407171715.GA22603@krava.redhat.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      54a50f93
    • W
      perf probe: Fix ARM 32 building error · f6c15621
      由 Wang Nan 提交于 
      Commit 9b118aca ("perf probe: Fix to
handle aliased symbols in glibc") uses an absolute format '%lx' to
print u64 argument, which causes compiling error on ARM 32.

This patch replaces it with PRIx64.
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Acked-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1428459274-138470-1-git-send-email-wangnan0@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      f6c15621
    • P
      perf tools: Merge all perf_event_attr print functions · 2c5e8c52
      由 Peter Zijlstra 提交于 
      Currently there's 3 (that I found) different and incomplete
implementations of printing perf_event_attr.

This is quite silly. Merge the lot.

While this patch does not retain the exact form all printing that I
found is debug output and thus it should not be critical.

Also, I cannot find a single print_event_desc() caller.

Pre:

 $ perf record -vv -e cycles -- sleep 1
 ------------------------------------------------------------
 perf_event_attr:
  type                0
  size                104
  config              0
  sample_period       4000
  sample_freq         4000
  sample_type         0x107
  read_format         0
  disabled            1    inherit             1
  pinned              0    exclusive           0
  exclude_user        0    exclude_kernel      0
  exclude_hv          0    exclude_idle        0
  mmap                1    comm                1
  mmap2               1    comm_exec           1
  freq                1    inherit_stat        0
  enable_on_exec      1    task                1
  watermark           0    precise_ip          0
  mmap_data           0    sample_id_all       1
  exclude_host        0    exclude_guest       1
  excl.callchain_kern 0    excl.callchain_user 0
  wakeup_events       0
  wakeup_watermark    0
  bp_type             0
  bp_addr             0
  config1             0
  bp_len              0
  config2             0
  branch_sample_type  0
  sample_regs_user    0
  sample_stack_user   0
  sample_regs_intr    0
 ------------------------------------------------------------

 $ perf evlist  -vv
 cycles: sample_freq=4000, size: 104, sample_type: IP|TID|TIME|PERIOD,
 disabled: 1, inherit: 1, mmap: 1, mmap2: 1, comm: 1, comm_exec: 1,
 freq: 1, enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1

 Post:

 $ ./perf record -vv -e cycles -- sleep 1
 ------------------------------------------------------------
 perf_event_attr:
  size                             112
  { sample_period, sample_freq }   4000
  sample_type                      IP|TID|TIME|PERIOD
  disabled                         1
  inherit                          1
  mmap                             1
  comm                             1
  freq                             1
  enable_on_exec                   1
  task                             1
  sample_id_all                    1
  exclude_guest                    1
  mmap2                            1
  comm_exec                        1
------------------------------------------------------------

 $ ./perf evlist  -vv
 cycles: size: 112, { sample_period, sample_freq }: 4000, sample_type:
 IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq:
 1, enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1,
 mmap2: 1, comm_exec: 1
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150407091150.644238729@infradead.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      2c5e8c52
    • P
      perf record: Add clockid parameter · 814c8c38
      由 Peter Zijlstra 提交于 
      Teach perf-record about the new perf_event_attr::{use_clockid, clockid}
fields. Add a simple parameter to set the clock (if any) to be used for
the events to be recorded into the data file.

Since we store the entire perf_event_attr in the EVENT_DESC section we
also already store the used clockid in the data file.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yunlong Song <yunlong.song@huawei.com>
Link: http://lkml.kernel.org/r/20150407154851.GR23123@twins.programming.kicks-ass.net
[ Conditionally define CLOCK_BOOTTIME, at least rhel6 doesn't have it - dsahern
  Ditto for CLOCK_MONOTONIC_RAW, sles11sp2 doesn't have it - yunlong.song ]
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      814c8c38
    • Y
      perf sched replay: Use replay_repeat to calculate the runavg of cpu usage... · ff5f3bbd
      由 Yunlong Song 提交于 
      perf sched replay: Use replay_repeat to calculate the runavg of cpu usage instead of the default value 10

Since sched->replay_repeat is set to 10 as default, the sched->run_avg,
sched->runavg_cpu_usage, and sched->runavg_parent_cpu_usage all use
10 to calculate their value.

However, the replay_repeat can be changed to other value by using -r
option, so the calculation above should use replay_repeat to achieve
more accurate results instead of the default value 10.
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/1427809596-29559-10-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      ff5f3bbd
    • Y
      perf sched replay: Support using -f to override perf.data file ownership · f0dd330f
      由 Yunlong Song 提交于 
      Enable to use perf.data when it is not owned by current user or root.

Example:

 $ ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 5321918 Mar 25 15:14 perf.data
 $ sudo id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 $ sudo perf sched replay -f
 run measurement overhead: 98 nsecs
 sleep measurement overhead: 52909 nsecs
 the run test took 1000015 nsecs
 the sleep test took 1054253 nsecs
 File perf.data not owned by current user or root (use -f to override)

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

After this patch:

 $ sudo perf sched replay -f
 run measurement overhead: 221 nsecs
 sleep measurement overhead: 40514 nsecs
 the run test took 1000003 nsecs
 the sleep test took 1056098 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   1549 (             :163132:    163132), nr_events: 1
 task   1550 (             :163540:    163540), nr_events: 1
 task   1551 (           <unknown>:         0), nr_events: 10
 ------------------------------------------------------------
 #1  : 50.198, ravg: 50.20, cpu: 2335.18 / 2335.18
 #2  : 219.099, ravg: 67.09, cpu: 2835.11 / 2385.17
 #3  : 238.626, ravg: 84.24, cpu: 3278.26 / 2474.48
 #4  : 200.364, ravg: 95.85, cpu: 2977.41 / 2524.77
 #5  : 176.882, ravg: 103.96, cpu: 2801.35 / 2552.43
 #6  : 191.093, ravg: 112.67, cpu: 2813.70 / 2578.56
 #7  : 189.448, ravg: 120.35, cpu: 2809.21 / 2601.62
 #8  : 200.637, ravg: 128.38, cpu: 2849.91 / 2626.45
 #9  : 248.338, ravg: 140.37, cpu: 4380.61 / 2801.87
 #10 : 511.139, ravg: 177.45, cpu: 3077.73 / 2829.45

As shown above, the -f option really works now.

Besides for replay, -f option can also work for latency and map.
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/1427809596-29559-9-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      f0dd330f
    • Y
      perf sched replay: Fix the EMFILE error caused by the limitation of the maximum open files · 939cda52
      由 Yunlong Song 提交于 
      The soft maximum number of open files for a calling process is 1024,
which is defined as INR_OPEN_CUR in include/uapi/linux/fs.h, and the
hard maximum number of open files for a calling process is 4096, which
is defined as INR_OPEN_MAX in include/uapi/linux/fs.h.

Both INR_OPEN_CUR and INR_OPEN_MAX are used to limit the value of
RLIMIT_NOFILE in include/asm-generic/resource.h.

And the soft maximum number finally decides the limitation of the
maximum files which are allowed to be opened.

That is to say a process can use at most 1024 file descriptors for its
o pened files, or an EMFILE error will happen.

This error can be fixed by increasing the soft maximum number, under the
constraint that the soft maximum number can not exceed the hard maximum
number, or both soft and hard maximum number should be increased
simultaneously with privilege.

For perf sched replay, it uses sys_perf_event_open to create the file
descriptor for each of the tasks in order to handle information of perf
events.

That is to say each task needs a unique file descriptor. In x86_64,
there may be over 1024 or 4096 tasks correspoinding to the record in
perf.data, which causes that no enough file descriptors can be used.

As a result, EMFILE error happens and stops the replay process. To solve
this problem, we adaptively increase the soft and hard maximum number of
open files with a '-f' option.

Example:

Test environment: x86_64 with 160 cores

 $ cat /proc/sys/kernel/pid_max
 163840
 $ cat /proc/sys/fs/file-max
 6815744
 $ ulimit -Sn
 1024
 $ ulimit -Hn
 4096

Before this patch:

 $ perf sched replay
 ...
 task   1549 (             :163132:    163132), nr_events: 1
 task   1550 (             :163540:    163540), nr_events: 1
 task   1551 (           <unknown>:         0), nr_events: 10
 Error: sys_perf_event_open() syscall returned with -1 (Too many open
 files)

After this patch:

 $ perf sched replay
 ...
 task   1549 (             :163132:    163132), nr_events: 1
 task   1550 (             :163540:    163540), nr_events: 1
 task   1551 (           <unknown>:         0), nr_events: 10
 Error: sys_perf_event_open() syscall returned with -1 (Too many open
 files)
 Have a try with -f option

 $ perf sched replay -f
 ...
 task   1549 (             :163132:    163132), nr_events: 1
 task   1550 (             :163540:    163540), nr_events: 1
 task   1551 (           <unknown>:         0), nr_events: 10
 ------------------------------------------------------------
 #1  : 54.401, ravg: 54.40, cpu: 3285.21 / 3285.21
 #2  : 199.548, ravg: 68.92, cpu: 4999.65 / 3456.66
 #3  : 170.483, ravg: 79.07, cpu: 1349.94 / 3245.99
 #4  : 192.034, ravg: 90.37, cpu: 1322.88 / 3053.67
 #5  : 182.929, ravg: 99.62, cpu: 1406.51 / 2888.96
 #6  : 152.974, ravg: 104.96, cpu: 1167.54 / 2716.82
 #7  : 155.579, ravg: 110.02, cpu: 2992.53 / 2744.39
 #8  : 130.557, ravg: 112.08, cpu: 1126.43 / 2582.59
 #9  : 138.520, ravg: 114.72, cpu: 1253.22 / 2449.65
 #10 : 134.328, ravg: 116.68, cpu: 1587.95 / 2363.48
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/1427809596-29559-8-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      939cda52
    • Y
      perf sched replay: Handle the dead halt of sem_wait when create_tasks() fails for any task · 1aff59be
      由 Yunlong Song 提交于 
      Since there is sem_wait for each task in the wait_for_tasks(), e.g.
sem_wait(&task->work_done_sem).

The sem_wait can continue only when work_done_sem is greater than 0, or
it will be blocked.

For perf sched replay, one task may sem_post the work_done_sem of
another task, which causes the work_done_sem of that task processed in a
reasonable sequence, e.g. sem_post, sem_wait, sem_wait, sem_post...

This sequence simulates the sched process of the running tasks at the
time when perf sched record runs.

As a result, all the tasks are required and their threads must be
successfully created.

If any one (task A) of the tasks fails to create its thread, then
another task (task B), whose work_done_sem needs sem_post from that
failed task A, may likely block itself due to seg_wait.

And this is a dead halt, since task B's thread_func cannot continue at
all.

To solve this problem, perf sched replay should exit once any task fails
to create its thread.

Example:

Test environment: x86_64 with 160 cores

Before this patch:

 $ perf sched replay
 ...
 Error: sys_perf_event_open() syscall returned with -1 (Too many open
 files)
 ------------------------------------------------------------    <- dead halt

After this patch:

 $ perf sched replay
 ...
 task   1551 (           <unknown>:         0), nr_events: 10
 Error: sys_perf_event_open() syscall returned with -1 (Too many open
 files)
 $

As shown above, perf sched replay finishes the process after printing an
error message and does not block itself.
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/1427809596-29559-7-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      1aff59be
    • Y
      perf sched replay: Fix the segmentation fault problem caused by pr_err in threads · 08097abc
      由 Yunlong Song 提交于 
      The pr_err in self_open_counters() prints error message to stderr.
Unlike stdout, stderr uses memory buffer on the stack of each calling
process.

The pr_err in self_open_counters() works in a thread called thread_func
created in function create_tasks, which concurrently creates
sched->nr_tasks threads.

If the error happens and pr_err prints the error message in each of
these threads, the stack size of the perf process (default is 8192
kbytes) will quickly run out and the segmentation fault will happen
then.

To solve this problem, pr_err with self_open_counters() should be moved
from newly created threads to the old main thread of the perf process.
Then the pr_err can work in a stable situation without the strange
segmentation fault problem.

Example:

Test environment: x86_64 with 160 cores

Before this patch:

 $ perf sched replay
 ...
 task   1549 (             :163132:    163132), nr_events: 1
 task   1550 (             :163540:    163540), nr_events: 1
 task   1551 (           <unknown>:         0), nr_events: 10
 Segmentation fault

After this patch:

 $ perf sched replay
 ...
 task   1549 (             :163132:    163132), nr_events: 1
 task   1550 (             :163540:    163540), nr_events: 1
 task   1551 (           <unknown>:         0), nr_events: 10
 ...

As shown above, the result continues without any segmentation fault.
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/1427809596-29559-6-git-send-email-yunlong.song@huawei.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      08097abc
    • Y
      perf sched replay: Realloc the memory of pid_to_task stepwise to adapt to the... · 3a423a5c
      由 Yunlong Song 提交于 
      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>
      3a423a5c
    • Y
      perf sched replay: Alloc the memory of pid_to_task dynamically to adapt to the... · cb06ac25
      由 Yunlong Song 提交于 
      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>
      cb06ac25