In this blog post, we’ll look at some of the available PMP profiling tools.

While debugging or analyzing issues with Percona Server for MySQL, we often need a quick understanding of what’s happening on the server. Percona experts frequently use the pt-pmp tool from Percona Toolkit (inspired by http://poormansprofiler.org).

The

pt-pmp

 tool collects application stack traces GDB and then post-processes them. From this you get a condensed, ordered list of the stack traces. The list helps you understand where the application spent most of the time: either running something or waiting for something.

Getting a profile with

Recently I was working with the output of pstack from a hung MySQL server and wanted to use Poor Man's Profiler in order to combine stack traces. Unfortunately, the awk magic expects the output from gdb's thread apply all bt output.

gdb output:

Thread 10 (Thread 0xa644db90 (LWP 26275)):
#0  0xb7f47410 in __kernel_vsyscall ()
#1  0xb7f33b1a in do_sigwait () from /lib/tls/i686/cmov/libpthread.so.0
#2  0xb7f33bbf in sigwait () from /lib/tls/i686/cmov/libpthread.so.0
#3  0x081cc4fc in signal_hand ()
#4  0xb7f2b4fb in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#5  0xb7d25e5e in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 9 (Thread 0xa641cb90 (LWP 26273)):
#0  0xb7f47410 in __kernel_vsyscall ()
#1  0xb7d1e881 in select …