This is the mail archive of the
systemtap@sourceware.org
mailing list for the systemtap project.
Re: [PATCH v4 2/3] Support for perf to probe into SDT markers:
- From: Pekka Enberg <penberg at iki dot fi>
- To: Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>
- Cc: Pekka Enberg <penberg at kernel dot org>, Hemant Kumar <hkshaw at linux dot vnet dot ibm dot com>, LKML <linux-kernel at vger dot kernel dot org>, Peter Zijlstra <peterz at infradead dot org>, Oleg Nesterov <oleg at redhat dot com>, "hegdevasant at linux dot vnet dot ibm dot com" <hegdevasant at linux dot vnet dot ibm dot com>, Ingo Molnar <mingo at redhat dot com>, "anton at redhat dot com" <anton at redhat dot com>, "systemtap at sourceware dot org" <systemtap at sourceware dot org>, Namhyung Kim <namhyung at kernel dot org>, Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>, "aravinda at linux dot vnet dot ibm dot com" <aravinda at linux dot vnet dot ibm dot com>
- Date: Fri, 25 Oct 2013 16:20:54 +0200
- Subject: Re: [PATCH v4 2/3] Support for perf to probe into SDT markers:
- Authentication-results: sourceware.org; auth=none
- References: <20131023044511 dot 1886 dot 82571 dot stgit at hemant-fedora> <20131023050502 dot 1886 dot 15779 dot stgit at hemant-fedora> <CAOJsxLFKm3TxeTmGjbpr1r4sZ8fHcM481-5BM_Cq0J8hhtvBqQ at mail dot gmail dot com> <20131025125921 dot GA29424 at linux dot vnet dot ibm dot com>
> Technically feasible. But then we would have to parse each of the
> libraries and executables to list them. Right? I am not sure if such a
> delay is acceptable.
You could do it at 'perf list' time or even build time and cache it. And add lazy discovery to 'perf record' and friends.
> Also if a binary exists in a path thats is not covered in the default
> search, an user might believe that his binary may not have markers.
> I know the above reason is more of a user folly than a tooling issue.
Lazy discovery at 'perf record'-time from executable and DSOs should make that transparent to the user, no? I'm pretty sure it will be fast enough with content-adressed cache.
- Pekka