CODEWITHSUNDEEP
linuxprofilingperf
ks1322
ks1322

Reputation: 35708

How to collect some readable stack traces with perf?

I want to profile C++ program on Linux using random sampling that is described in this answer:

However, if you're in a hurry and you can manually interrupt your program under the debugger while it's being subjectively slow, there's a simple way to find performance problems.

The problem is that I can't use gdb debugger because I want to profile on production under heavy load and debugger is too intrusive and considerably slows down the program. However I can use perf record and perf report for finding bottlenecks without affecting program performance. Is there a way to collect a number of readable (gdb like) stack traces with perf instead of gdb?

Upvotes: 3

Views: 2166

Answers (1)

Zulan
Zulan

Reputation: 22660

perf does offer callstack recording with three different techniques

  • By default is uses the frame pointer (fp). This is generally supported and performs well, but it doesn't work with certain optimizations. Compile your applications with -fno-omit-frame-pointer etc. to make sure it works well.
  • dwarf uses a dump of the sack for each sample for post-processing. That has a significant performance penalty
  • Modern systems can use hardware-supported last branch record, lbr.

The stack is accessible in perf analysis tools such as perf report or perf script.

For more details check out man perf-record.

Upvotes: 2

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