Ask HN: What's your best C/C++ profiling tool, hints and best practice?

#1

Post by henrikm85 » Sun, Aug 23, 2015, 12:54 AM UTC

I frequently come across wanting to profile C++ on Linux. I have used perf a lot before but do not have vtune handy. I have dabbled around with poor man's profiler but that seems to get trickier with lots and lots of threads. What are your favorite outside-the-box approaches? How do you figure out contention or IO wait issues?

Re: Ask HN: What's your best C/C++ profiling tool, hints and best practice?

#2

Post by soulbadguy » Sun, Aug 23, 2015, 2:13 AM UTC

Very interested in this too

Re: Ask HN: What's your best C/C++ profiling tool, hints and best practice?

#3

Post by [deleted] » Sun, Aug 23, 2015, 2:23 AM UTC

[deleted]

Re: Ask HN: What's your best C/C++ profiling tool, hints and best practice?

#4

Post by olzhas » Sun, Aug 23, 2015, 2:23 AM UTC

soulbadguy wrote: post #2

Very interested in this too

me too

Re: Ask HN: What's your best C/C++ profiling tool, hints and best practice?

#5

Post by zubairsaif007 » Sun, Aug 23, 2015, 2:41 AM UTC

http://googler700.blogspot.com/

Re: Ask HN: What's your best C/C++ profiling tool, hints and best practice?

#6

Post by vandot » Sun, Aug 23, 2015, 2:51 AM UTC

HPCToolkit and TAU are good options for profiling C++ applications. They come from HPC so they are intended for use with parallel and highly concurrent applications.

http://hpctoolkit.org/ https://www.cs.uoregon.edu/research/tau/home.php

Re: Ask HN: What's your best C/C++ profiling tool, hints and best practice?

#7

Post by gricardo99 » Sun, Aug 23, 2015, 4:26 AM UTC

valgrind's got some good features along these lines: http://valgrind.org/info/tools.html

Re: Ask HN: What's your best C/C++ profiling tool, hints and best practice?

#8

Post by henrikm85 » Sun, Aug 23, 2015, 5:28 AM UTC

gricardo99 wrote: post #7

valgrind's got some good features along these lines: http://valgrind.org/info/tools.html

Valgrind is nice, however, especially with multi-threaded programs the virtualized execution diverges from a non-valgrind-VM run quite a bit so I am not a huge fan.

Re: Ask HN: What's your best C/C++ profiling tool, hints and best practice?

#9

Post by Ologn » Sun, Aug 23, 2015, 5:30 AM UTC

gricardo99 wrote: post #7

valgrind's got some good features along these lines: http://valgrind.org/info/tools.html

Valgrind is good.

Gprof is good too.

Re: Ask HN: What's your best C/C++ profiling tool, hints and best practice?

#10

Post by ekr » Sun, Aug 23, 2015, 12:20 PM UTC

Any tips on profiling windows device drivers? I've tried xperf, but it doesn't allow you (or I haven't seen how) to change the frequency of the sampling, and can only do a system-wide profile.

I've also tried vtune, but it doesn't support stack-tracing (or things like lbr) for system-wide profiling, and it doesn't have a specific option for sampling drivers. You can attach to the System process, but then you're missing a lot of the your driver code, that runs in other contexts.

I kept thinking about implementing my own sampling profiler (using LBR for stack-tracing, and hardware performance events, like linux's oprofile/ freebsd's hwpmc), but I can't see how I could only profile my driver, and not the whole system, without hooking the Windows scheduler. I guess I will just profile the whole system and check if the program counter is inside my module.