Debuglib

layout: post
title: “Debug lib in Linux”
date: 2019-08-28 12:25:06
description: lib and performance debug
tags:

• code

Command

• ldd
  ldd /usr/sbin/apache2|grep libc.so
  libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f2a337d8000)
• create probe
  perf probe -x /lib/x86_64-linux-gnu/libc.so.6 malloc
  perf probe -l

• record
  perf record -e probe_libc:malloc -a -p 15640 –call-graph dwarf
  perf report

• result
  ```
  Samples: 3K of event ‘probe_libc:malloc’, Event count (approx.): 3770
  Children Self Command Shared Object Symbol ▒
• 99.89% 99.89% java libc-2.19.so [.] malloc ▒
• 32.07% 0.00% java perf-30529.map [.] 0x00007fcd4d37c827 ◆
• 32.07% 0.00% java libsunec.so [.] Java_sun_security_ec_ECKeyPairGenerator_generateECKeyPair ▒
• 31.91% 0.00% java perf-30529.map [.] 0x00007fcd4d383675 ▒
• 31.91% 0.00% java libsunec.so [.] Java_sun_security_ec_ECDHKeyAgreement_deriveKey ▒
• 23.47% 0.00% java libc-2.19.so [.] __strdup ▒
• 21.72% 0.00% java libsunec.so [.] 0x000000000000ab61 ▒
• 21.09% 0.00% java libsunec.so [.] 0x0000000000010158
  ```