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  1. 01 4月, 2013 2 次提交
  3. 18 3月, 2013 3 次提交
    • N
      perf/cgroup: Add __percpu annotation to perf_cgroup->info · 86e213e1
      由 Namhyung Kim 提交于 
      It's a per-cpu data structure but missed the __percpu annotation.
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Link: http://lkml.kernel.org/r/1363600594-11453-1-git-send-email-namhyung@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      86e213e1
    • N
      perf: Generate EXIT event only once per task context · d610d98b
      由 Namhyung Kim 提交于 
      perf_event_task_event() iterates pmu list and generate events
for each eligible pmu context.  But if task_event has task_ctx
like in EXIT it'll generate events even though the pmu doesn't
have an eligible one. Fix it by moving the code to proper
places.

Before this patch:

  $ perf record -n true
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.006 MB perf.data (~248 samples) ]

  $ perf report -D | tail
  Aggregated stats:
             TOTAL events:         73
              MMAP events:         67
              COMM events:          2
              EXIT events:          4
  cycles stats:
             TOTAL events:         73
              MMAP events:         67
              COMM events:          2
              EXIT events:          4

After this patch:

  $ perf report -D | tail
  Aggregated stats:
             TOTAL events:         70
              MMAP events:         67
              COMM events:          2
              EXIT events:          1
  cycles stats:
             TOTAL events:         70
              MMAP events:         67
              COMM events:          2
              EXIT events:          1
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1363332433-7637-1-git-send-email-namhyung@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      d610d98b
    • N
      perf: Reset hwc->last_period on sw clock events · 778141e3
      由 Namhyung Kim 提交于 
      When cpu/task clock events are initialized, their sampling
frequencies are converted to have a fixed value.  However it
missed to update the hwc->last_period which was set to 1 for
initial sampling frequency calibration.

Because this hwc->last_period value is used as a period in
perf_swevent_ hrtime(), every recorded sample will have an
incorrected period of 1.

  $ perf record -e task-clock noploop 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.158 MB perf.data (~6919 samples) ]

  $ perf report -n --show-total-period  --stdio
  # Samples: 4K of event 'task-clock'
  # Event count (approx.): 4000
  #
  # Overhead       Samples        Period  Command  Shared Object              Symbol
  # ........  ............  ............  .......  .............  ..................
  #
      99.95%          3998          3998  noploop  noploop        [.] main
       0.03%             1             1  noploop  libc-2.15.so   [.] init_cacheinfo
       0.03%             1             1  noploop  ld-2.15.so     [.] open_verify

Note that it doesn't affect the non-sampling event so that the
perf stat still gets correct value with or without this patch.

  $ perf stat -e task-clock noploop 1

   Performance counter stats for 'noploop 1':

         1000.272525 task-clock                #    1.000 CPUs utilized

         1.000560605 seconds time elapsed
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1363574507-18808-1-git-send-email-namhyung@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      778141e3
  5. 06 3月, 2013 1 次提交
  7. 28 2月, 2013 2 次提交
    • S
      hlist: drop the node parameter from iterators · b67bfe0d
      由 Sasha Levin 提交于 
      I'm not sure why, but the hlist for each entry iterators were conceived

        list_for_each_entry(pos, head, member)

The hlist ones were greedy and wanted an extra parameter:

        hlist_for_each_entry(tpos, pos, head, member)

Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.

Besides the semantic patch, there was some manual work required:

 - Fix up the actual hlist iterators in linux/list.h
 - Fix up the declaration of other iterators based on the hlist ones.
 - A very small amount of places were using the 'node' parameter, this
 was modified to use 'obj->member' instead.
 - Coccinelle didn't handle the hlist_for_each_entry_safe iterator
 properly, so those had to be fixed up manually.

The semantic patch which is mostly the work of Peter Senna Tschudin is here:

@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;

type T;
expression a,c,d,e;
identifier b;
statement S;
@@

-T b;
    <+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
    ...+>

[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: NPeter Senna Tschudin <peter.senna@gmail.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b67bfe0d
    • T
      events: convert to idr_alloc() · 0e9c3be2
      由 Tejun Heo 提交于 
      Convert to the much saner new idr interface.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      0e9c3be2
  9. 23 2月, 2013 1 次提交
  11. 09 2月, 2013 1 次提交
    • O
      perf: Introduce hw_perf_event->tp_target and ->tp_list · f22c1bb6
      由 Oleg Nesterov 提交于 
      sys_perf_event_open()->perf_init_event(event) is called before
find_get_context(event), this means that event->ctx == NULL when
class->reg(TRACE_REG_PERF_REGISTER/OPEN) is called and thus it
can't know if this event is per-task or system-wide.

This patch adds hw_perf_event->tp_target for PERF_TYPE_TRACEPOINT,
this is analogous to PERF_TYPE_BREAKPOINT/bp_target we already have.
The patch also moves ->bp_target up so that it can overlap with the
new member, this can help the compiler to generate the better code.

trace_uprobe_register() will use it for prefiltering to avoid the
unnecessary breakpoints in mm's we do not want to trace.

->tp_target doesn't have its own reference, but we can rely on the
fact that either sys_perf_event_open() holds a reference, or it is
equal to event->ctx->task. So this pointer is always valid until
free_event().

Also add the "struct list_head tp_list" into this union. It is not
strictly necessary, but it can simplify the next changes and we can
add it for free.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
      f22c1bb6
  13. 03 2月, 2013 1 次提交
  15. 20 11月, 2012 1 次提交
  17. 19 11月, 2012 1 次提交
    • E
      pidns: Use task_active_pid_ns where appropriate · 17cf22c3
      由 Eric W. Biederman 提交于 
      The expressions tsk->nsproxy->pid_ns and task_active_pid_ns
aka ns_of_pid(task_pid(tsk)) should have the same number of
cache line misses with the practical difference that
ns_of_pid(task_pid(tsk)) is released later in a processes life.

Furthermore by using task_active_pid_ns it becomes trivial
to write an unshare implementation for the the pid namespace.

So I have used task_active_pid_ns everywhere I can.

In fork since the pid has not yet been attached to the
process I use ns_of_pid, to achieve the same effect.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
      17cf22c3
  19. 09 10月, 2012 1 次提交
    • K
      mm: kill vma flag VM_RESERVED and mm->reserved_vm counter · 314e51b9
      由 Konstantin Khlebnikov 提交于 
      A long time ago, in v2.4, VM_RESERVED kept swapout process off VMA,
currently it lost original meaning but still has some effects:

 | effect                 | alternative flags
-+------------------------+---------------------------------------------
1| account as reserved_vm | VM_IO
2| skip in core dump      | VM_IO, VM_DONTDUMP
3| do not merge or expand | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP
4| do not mlock           | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP

This patch removes reserved_vm counter from mm_struct.  Seems like nobody
cares about it, it does not exported into userspace directly, it only
reduces total_vm showed in proc.

Thus VM_RESERVED can be replaced with VM_IO or pair VM_DONTEXPAND | VM_DONTDUMP.

remap_pfn_range() and io_remap_pfn_range() set VM_IO|VM_DONTEXPAND|VM_DONTDUMP.
remap_vmalloc_range() set VM_DONTEXPAND | VM_DONTDUMP.

[akpm@linux-foundation.org: drivers/vfio/pci/vfio_pci.c fixup]
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      314e51b9
  21. 05 10月, 2012 2 次提交
  23. 27 9月, 2012 2 次提交
  25. 15 9月, 2012 1 次提交
    • T
      cgroup: mark subsystems with broken hierarchy support and whine if cgroups are nested for them · 8c7f6edb
      由 Tejun Heo 提交于 
      Currently, cgroup hierarchy support is a mess.  cpu related subsystems
behave correctly - configuration, accounting and control on a parent
properly cover its children.  blkio and freezer completely ignore
hierarchy and treat all cgroups as if they're directly under the root
cgroup.  Others show yet different behaviors.

These differing interpretations of cgroup hierarchy make using cgroup
confusing and it impossible to co-mount controllers into the same
hierarchy and obtain sane behavior.

Eventually, we want full hierarchy support from all subsystems and
probably a unified hierarchy.  Users using separate hierarchies
expecting completely different behaviors depending on the mounted
subsystem is deterimental to making any progress on this front.

This patch adds cgroup_subsys.broken_hierarchy and sets it to %true
for controllers which are lacking in hierarchy support.  The goal of
this patch is two-fold.

* Move users away from using hierarchy on currently non-hierarchical
  subsystems, so that implementing proper hierarchy support on those
  doesn't surprise them.

* Keep track of which controllers are broken how and nudge the
  subsystems to implement proper hierarchy support.

For now, start with a single warning message.  We can whine louder
later on.

v2: Fixed a typo spotted by Michal. Warning message updated.

v3: Updated memcg part so that it doesn't generate warning in the
    cases where .use_hierarchy=false doesn't make the behavior
    different from root.use_hierarchy=true.  Fixed a typo spotted by
    Glauber.

v4: Check ->broken_hierarchy after cgroup creation is complete so that
    ->create() can affect the result per Michal.  Dropped unnecessary
    memcg root handling per Michal.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Acked-by: NLi Zefan <lizefan@huawei.com>
Acked-by: NSerge E. Hallyn <serue@us.ibm.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      8c7f6edb
  27. 04 9月, 2012 2 次提交
  29. 10 8月, 2012 2 次提交
    • J
      perf: Add ability to attach user stack dump to sample · c5ebcedb
      由 Jiri Olsa 提交于 
      Introducing PERF_SAMPLE_STACK_USER sample type bit to trigger the dump
of the user level stack on sample. The size of the dump is specified by
sample_stack_user value.

Being able to dump parts of the user stack, starting from the stack
pointer, will be useful to make a post mortem dwarf CFI based stack
unwinding.

Added HAVE_PERF_USER_STACK_DUMP config option to determine if the
architecture provides user stack dump on perf event samples.  This needs
access to the user stack pointer which is not unified across
architectures. Enabling this for x86 architecture.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Original-patch-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Arun Sharma <asharma@fb.com>
Cc: Benjamin Redelings <benjamin.redelings@nescent.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Ulrich Drepper <drepper@gmail.com>
Link: http://lkml.kernel.org/r/1344345647-11536-6-git-send-email-jolsa@redhat.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      c5ebcedb
    • J
      perf: Add ability to attach user level registers dump to sample · 4018994f
      由 Jiri Olsa 提交于 
      Introducing PERF_SAMPLE_REGS_USER sample type bit to trigger the dump of
user level registers on sample. Registers we want to dump are specified
by sample_regs_user bitmask.

Only user level registers are dumped at the moment. Meaning the register
values of the user space context as it was before the user entered the
kernel for whatever reason (syscall, irq, exception, or a PMI happening
in userspace).

The layout of the sample_regs_user bitmap is described in
asm/perf_regs.h for archs that support register dump.

This is going to be useful to bring Dwarf CFI based stack unwinding on
top of samples.
Original-patch-by: NFrederic Weisbecker <fweisbec@gmail.com>
[ Dump registers ABI specification. ]
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Suggested-by: NStephane Eranian <eranian@google.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Arun Sharma <asharma@fb.com>
Cc: Benjamin Redelings <benjamin.redelings@nescent.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Ulrich Drepper <drepper@gmail.com>
Link: http://lkml.kernel.org/r/1344345647-11536-3-git-send-email-jolsa@redhat.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      4018994f
  31. 31 7月, 2012 1 次提交
  33. 18 6月, 2012 4 次提交
  35. 01 6月, 2012 1 次提交
  37. 23 5月, 2012 1 次提交
    • J
      Revert "sched, perf: Use a single callback into the scheduler" · ab0cce56
      由 Jiri Olsa 提交于 
      This reverts commit cb04ff9a ("sched, perf: Use a single
callback into the scheduler").

Before this change was introduced, the process switch worked
like this (wrt. to perf event schedule):

     schedule (prev, next)
       - schedule out all perf events for prev
       - switch to next
       - schedule in all perf events for current (next)

After the commit, the process switch looks like:

     schedule (prev, next)
       - schedule out all perf events for prev
       - schedule in all perf events for (next)
       - switch to next

The problem is, that after we schedule perf events in, the pmu
is enabled and we can receive events even before we make the
switch to next - so "current" still being prev process (event
SAMPLE data are filled based on the value of the "current"
process).

Thats exactly what we see for test__PERF_RECORD test. We receive
SAMPLES with PID of the process that our tracee is scheduled
from.

Discussed with Peter Zijlstra:

 > Bah!, yeah I guess reverting is the right thing for now. Sad
 > though.
 >
 > So by having the two hooks we have a black-spot between them
 > where we receive no events at all, this black-spot covers the
 > hand-over of current and we thus don't receive the 'wrong'
 > events.
 >
 > I rather liked we could do away with both that black-spot and
 > clean up the code a little, but apparently people rely on it.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: acme@redhat.com
Cc: paulus@samba.org
Cc: cjashfor@linux.vnet.ibm.com
Cc: fweisbec@gmail.com
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/20120523111302.GC1638@m.brq.redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      ab0cce56
  39. 09 5月, 2012 2 次提交
  41. 26 4月, 2012 2 次提交
  43. 24 3月, 2012 1 次提交
  45. 23 3月, 2012 1 次提交
    • P
      perf: Fix mmap_page capabilities and docs · c7206205
      由 Peter Zijlstra 提交于 
      Complete the syscall-less self-profiling feature and address
all complaints, namely:

 - capabilities, so we can detect what is actually available at runtime

     Add a capabilities field to perf_event_mmap_page to indicate
     what is actually available for use.

 - on x86: RDPMC weirdness due to being 40/48 bits and not sign-extending
   properly.

 - ABI documentation as to how all this stuff works.

Also improve the documentation for the new features.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vweaver1@eecs.utk.edu>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1332433596.2487.33.camel@twinsSigned-off-by: NIngo Molnar <mingo@kernel.org>
      c7206205
  47. 05 3月, 2012 3 次提交
    • S
      perf: Add callback to flush branch_stack on context switch · d010b332
      由 Stephane Eranian 提交于 
      With branch stack sampling, it is possible to filter by priv levels.

In system-wide mode, that means it is possible to capture only user
level branches. The builtin SW LBR filter needs to disassemble code
based on LBR captured addresses. For that, it needs to know the task
the addresses are associated with. Because of context switches, the
content of the branch stack buffer may contain addresses from
different tasks.

We need a callback on context switch to either flush the branch stack
or save it. This patch adds a new callback in struct pmu which is called
during context switches. The callback is called only when necessary.
That is when a system-wide context has, at least, one event which
uses PERF_SAMPLE_BRANCH_STACK. The callback is never called for
per-thread context.

In this version, the Intel x86 code simply flushes (resets) the LBR
on context switches (fills it with zeroes). Those zeroed branches are
then filtered out by the SW filter.
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1328826068-11713-11-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@elte.hu>
      d010b332
    • S
      perf: Disable PERF_SAMPLE_BRANCH_* when not supported · 2481c5fa
      由 Stephane Eranian 提交于 
      PERF_SAMPLE_BRANCH_* is disabled for:

 - SW events (sw counters, tracepoints)
 - HW breakpoints
 - ALL but Intel x86 architecture
 - AMD64 processors
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1328826068-11713-10-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@elte.hu>
      2481c5fa
    • S
      perf: Add generic taken branch sampling support · bce38cd5
      由 Stephane Eranian 提交于 
      This patch adds the ability to sample taken branches to the
perf_event interface.

The ability to capture taken branches is very useful for all
sorts of analysis. For instance, basic block profiling, call
counts, statistical call graph.

This new capability requires hardware assist and as such may
not be available on all HW platforms. On Intel x86 it is
implemented on top of the Last Branch Record (LBR) facility.

To enable taken branches sampling, the PERF_SAMPLE_BRANCH_STACK
bit must be set in attr->sample_type.

Sampled taken branches may be filtered by type and/or priv
levels.

The patch adds a new field, called branch_sample_type, to the
perf_event_attr structure. It contains a bitmask of filters
to apply to the sampled taken branches.

Filters may be implemented in HW. If the HW filter does not exist
or is not good enough, some arch may also implement a SW filter.

The following generic filters are currently defined:
- PERF_SAMPLE_USER
  only branches whose targets are at the user level

- PERF_SAMPLE_KERNEL
  only branches whose targets are at the kernel level

- PERF_SAMPLE_HV
  only branches whose targets are at the hypervisor level

- PERF_SAMPLE_ANY
  any type of branches (subject to priv levels filters)

- PERF_SAMPLE_ANY_CALL
  any call branches (may incl. syscall on some arch)

- PERF_SAMPLE_ANY_RET
  any return branches (may incl. syscall returns on some arch)

- PERF_SAMPLE_IND_CALL
  indirect call branches

Obviously filter may be combined. The priv level bits are optional.
If not provided, the priv level of the associated event are used. It
is possible to collect branches at a priv level different from the
associated event. Use of kernel, hv priv levels is subject to permissions
and availability (hv).

The number of taken branch records present in each sample may vary based
on HW, the type of sampled branches, the executed code. Therefore
each sample contains the number of taken branches it contains.
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1328826068-11713-2-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@elte.hu>
      bce38cd5
  49. 24 2月, 2012 1 次提交
    • I
      static keys: Introduce 'struct static_key', static_key_true()/false() and... · c5905afb
      由 Ingo Molnar 提交于 
      static keys: Introduce 'struct static_key', static_key_true()/false() and static_key_slow_[inc|dec]()

So here's a boot tested patch on top of Jason's series that does
all the cleanups I talked about and turns jump labels into a
more intuitive to use facility. It should also address the
various misconceptions and confusions that surround jump labels.

Typical usage scenarios:

        #include <linux/static_key.h>

        struct static_key key = STATIC_KEY_INIT_TRUE;

        if (static_key_false(&key))
                do unlikely code
        else
                do likely code

Or:

        if (static_key_true(&key))
                do likely code
        else
                do unlikely code

The static key is modified via:

        static_key_slow_inc(&key);
        ...
        static_key_slow_dec(&key);

The 'slow' prefix makes it abundantly clear that this is an
expensive operation.

I've updated all in-kernel code to use this everywhere. Note
that I (intentionally) have not pushed through the rename
blindly through to the lowest levels: the actual jump-label
patching arch facility should be named like that, so we want to
decouple jump labels from the static-key facility a bit.

On non-jump-label enabled architectures static keys default to
likely()/unlikely() branches.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NJason Baron <jbaron@redhat.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: a.p.zijlstra@chello.nl
Cc: mathieu.desnoyers@efficios.com
Cc: davem@davemloft.net
Cc: ddaney.cavm@gmail.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20120222085809.GA26397@elte.huSigned-off-by: NIngo Molnar <mingo@elte.hu>
      c5905afb