Re: [PATCH v4 2/3] Support for perf to probe into SDT markers:
From: Frank Ch. Eigler
Date: Sat Oct 26 2013 - 07:17:06 EST
Pekka Enberg <penberg@xxxxxxxxxx> writes:
> Is there a technical reason why 'perf list' could not show all the
> available SDT markers on a system and that the 'mark to event'
> mapping cannot happen automatically? [...]
A quick experiment with:
find `echo $PATH | tr : ' '` -type f -perm -555 |
xargs readelf -n 2>/dev/null |
grep STAP 2>/dev/null
suggests reasonable performance for my F19 workstation (a second or
two over ~6000 executables), once all the ELF content is in the block
cache. According to a stap eventcount.stp run, that required about
50000 syscall.read events.
Note that a $PATH search excludes shared libraries, which can also
carry <sys/sdt.h> markers. Adding /usr/lib* in more than doubles the
work, then there's /usr/libexec etc.
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