Re: [PATCH v4 2/3] Support for perf to probe into SDT markers:
From: Masami Hiramatsu
Date: Wed Oct 30 2013 - 06:05:52 EST
(2013/10/26 20:16), Frank Ch. Eigler wrote:
> 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.
To find all system libraries, we can use ldconfig.
$ ldconfig --print-cache
shows what dynamic libraries will be loaded. On my own laptop (running
ubuntu13.04) shows ~1000 libs.
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
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