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  1. 23 Dec, 2011 4 commits
    • Ingo Molnar's avatar
      perf tools: Fix truncated annotation · f41612f4
      Ingo Molnar authored 
      I get such truncated annotation results in 'perf top':

         :        Disassembly of section .text:                                                   ▒
         :                                                                                        ▒
         :        ffffffff810966a8 <nr_iowait_cpu>:                                               ▒
    4.94 :        ffffffff810966a8:       movslq %edi,%rdi                                        ▒
    3.70 :        ffffffff810966ab:       mov    $0x13700,%rax                                    ▒
    0.00 :        ffffffff810966b2:       add    -0x7e32cb00(,%rdi,8),%rax                        ▒
    8.64 :        ffffffff810966ba:       mov    0x7e0(%rax),%eax                                 ▒
   82.72 :        ffffffff810966c0:       cltq                                                    ▒

Note the missing 'retq' which is there in the original function:

ffffffff810966a8 <nr_iowait_cpu>:
ffffffff810966a8:       48 63 ff                movslq %edi,%rdi
ffffffff810966ab:       48 c7 c0 00 37 01 00    mov    $0x13700,%rax
ffffffff810966b2:       48 03 04 fd 00 35 cd    add    -0x7e32cb00(,%rdi,8),%rax
ffffffff810966b9:       81
ffffffff810966ba:       8b 80 e0 07 00 00       mov    0x7e0(%rax),%eax
ffffffff810966c0:       48 98                   cltq
ffffffff810966c2:       c3                      retq

ffffffff810966c3 <this_cpu_load>:

I'm using a fairly recent binutils:

  GNU objdump version 2.21.51.0.6-2.fc16 20110118

AFAICS the bug is simply that sym->end points to the last byte
of the symbol in question - while objdump's --stop-address
expects the last byte plus 1 to disassemble the full range.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20111223130804.GA24305@elte.huSigned-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      f41612f4
    • David Ahern's avatar
      perf script: look up thread using tid instead of pid · 64aab93c
      David Ahern authored 
      This allows the thread name to be dispalyed when dumping
events:
           myapp 25118 [000] 450385.538815: context-switches ...
    myapp:worker 25119 [000] 450385.538894: context-switches ...

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1324578603-12762-4-git-send-email-dsahern@gmail.comSigned-off-by: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      64aab93c
    • David Ahern's avatar
      perf tools: Look up thread names for system wide profiling · f5faf726
      David Ahern authored 
      This handles multithreaded processes with named threads when doing
system wide profiling: the comm for each thread is looked up allowing
them to be different from the thread group leader.

v2:
- fixed sizeof arg to perf_event__get_comm_tgid

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1324578603-12762-3-git-send-email-dsahern@gmail.comSigned-off-by: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      f5faf726
    • David Ahern's avatar
      perf tools: Fix comm for processes with named threads · defd8d38
      David Ahern authored 
      perf does not properly handle monitoring of processes with named threads.
For example:

$ ps -C myapp -L
  PID   LWP TTY          TIME CMD
25118 25118 ?        00:00:00 myapp
25118 25119 ?        00:00:00 myapp:worker

perf record -e cs -c 1 -fo /tmp/perf.data -p 25118 -- sleep 10
perf report --stdio -i /tmp/perf.data
   100.00%  myapp:worker  [kernel.kallsyms]  [k] perf_event_task_sched_out

The process name is set to the name of the last thread it finds for the
process.

The Problem:
perf-top and perf-record both create a thread_map of threads to be
monitored. That map is used in perf_event__synthesize_thread_map which
loops over the entries in thread_map and calls __event__synthesize_thread
to generate COMM and MMAP events.

__event__synthesize_thread calls perf_event__synthesize_comm which opens
/proc/pid/status, reads the name of the task and its thread group id.
That's all fine. The problem is that it then reads /proc/pid/task and
generates COMM events for each task it finds - but using the name found
in /proc/pid/status where pid is the thread of interest.

The end result (looping over thread_map + synthesizing comm events for
each thread each time) means the name of the last thread processed sets
the name for all threads in the process - which is not good for
multithreaded processes with named threads.

The Fix:
perf_event__synthesize_comm has an input argument (full) that decides
whether to process task entries for each pid it is passed. It currently
never set to 0 (perf_event__synthesize_comm has a single caller and it
always passes the value 1). Let's fix that.

Add the full input argument to __event__synthesize_thread which passes
it to perf_event__synthesize_comm. For thread/process monitoring set full
to 0 which means COMM and MMAP events are only generated for the pid
passed to it. For system wide monitoring set full to 1 so that COMM events
are generated for all threads in a process.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1324578603-12762-2-git-send-email-dsahern@gmail.comSigned-off-by: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      defd8d38
  3. 22 Dec, 2011 1 commit
  5. 21 Dec, 2011 4 commits
  7. 20 Dec, 2011 13 commits
  9. 17 Dec, 2011 1 commit
  11. 16 Dec, 2011 17 commits
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