[Bug 198147] [hwpmc] running pmcstat -t (top mode) whilst a process is running doesn't resolve the symbols correctly

bugzilla-noreply at freebsd.org bugzilla-noreply at freebsd.org
Fri May 8 20:34:45 UTC 2015


https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=198147

John Baldwin <jhb at FreeBSD.org> changed:

           What    |Removed                     |Added
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                 CC|                            |jhb at FreeBSD.org

--- Comment #3 from John Baldwin <jhb at FreeBSD.org> ---
I definitely see this here in my same test setup as the other bug.  I've never
gotten it resolve any user symbols in fact, but I've always been running
pmcstat after starting the process:

PMC: [branch-instruction-retired] Samples: 351879 (100.0%) , 350556 unresolved

%SAMP IMAGE      FUNCTION             CALLERS
 50.2 kernel     _mtx_lock_spin_cooki __mtx_lock_spin_flags
  9.4 kernel     spinlock_exit        _mtx_lock_spin_cookie:5.1 ...
  5.4 hwpmc.ko   pmclog_process_callc pmc_process_samples
  5.4 kernel     __mtx_lock_spin_flag pmclog_reserve
  4.2 hwpmc.ko   pmclog_reserve       pmclog_process_callchain
  3.3 kernel     spinlock_enter       _mtx_lock_spin_cookie:1.5 ...
  3.0 hwpmc.ko   pmc_process_samples  pmc_hook_handler
  2.7 kernel     __mtx_unlock_spin_fl pmclog_release
  2.6 hwpmc.ko   soft_get_config      pmc_process_samples
  1.9 kernel     critical_exit        spinlock_exit
  1.7 kernel     atomic_subtract_barr pmc_process_samples
  1.2 hwpmc.ko   pmclog_release       pmc_process_samples
  1.1 kernel     witness_lock         pmclog_reserve
  0.6 kernel     witness_unlock       __mtx_unlock_spin_flags
  0.6 kernel     critical_enter
  0.6 kernel     cpu_search_lowest
  0.5 kernel     witness_checkorder
  0.5 hwpmc.ko   iap_get_config

(Nothing from threadspin, and it was built with -g)

If I run threadspin directly instead of using -t `pgrep threadspin`, then it
works:

PMC: [branch-instruction-retired] Samples: 162009 (100.0%) , 0 unresolved

%SAMP IMAGE      FUNCTION             CALLERS
 99.7 threadspin worker               0x8744

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