Messages in this thread | | | Date | Fri, 18 May 2012 12:49:47 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH 1/2] perf: Add persistent event facilities |
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On Fri, May 18, 2012 at 12:09:13PM +0200, Peter Zijlstra wrote: > On Wed, 2012-03-21 at 15:34 +0100, Borislav Petkov wrote: > > + persistent : 1, /* always-on event */ > > Should creating something like that be privileged?
Yeah, I dunno, do we want that? Well, what it is when we enable an event during boot, i.e. say "boot_trace=<event>..." on the kernel command line and this event is enabled until we finish booting. Then we disable it with perf or over debugfs. Is that privileged or can any user boot-trace the system?
All good questions.
> And it looks like you allow creating persistent per-task events; is > that useful, if so why? And like already pointed out, your cleanup > seems broken in that case.
This was dumb - I wanted to have task-agnostic events which get enabled for the whole system and there's a buffer on each CPU which collects their output. It was a first attempt and it is a good thing you gave it a look so that I can address the issues properly.
Thanks.
-- Regards/Gruss, Boris.
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