Jolsa Docs Annotations

Latest revision as of 18:55, 9 July 2013

[edit] ANNOTATIONS

TODO: description & examples

The perf annotations is based on objdump tool from binutils package.

[edit] BINUTILS RESTRICTIONS

Annotations are based on debuginfo, which on most (Fedora) distributions come in separated *-debuginfo packages. Unfortunately objdump does not connect binaries with its debuginfo counterparts.

The result is that for binaries with separated debuginfo you'll not see annotations in perf.

[edit] WORKAROUND

There's a following workaround, that merges debuginfo back to the binary. Such binary will display proper annotations in perf.

The binary we want to annotate properly is ls.

• find out the debuginfo holder:

$ rpm -ql coreutils-debuginfo | grep ls.debug
/usr/lib/debug/usr/bin/ls.debug

• OPTIONAL if your distribution uses prelink, you need to undo it:

$ cp /bin/ls .
$ prelink -u ls

• create the ls-di binary with debuginfo merged:

$ eu-unstrip -o ls-di ./ls /usr/lib/debug/usr/bin/ls.debug
$ file ls-di
ls-di: ELF 64-bit LSB executable, x86-64, version 1 (SYSV) [SNIP] not stripped

• clean the build-id cache, since the ls share same build-id with ls-di:

$ perf buildid-cache -r ls
# or more efectively:
$ rm -rf ~/.debug/

• enjoy your annotations via:

$ perf record ./ls-di [SNIP]
$ perf annotate [FUNC]
$ perf report