From: fche@redhat.com (Frank Ch. Eigler)
To: "Stone, Joshua I" <joshua.i.stone@intel.com>
Cc: systemtap@sources.redhat.com
Subject: Re: Proposed systemtap access to perfmon hardware
Date: Wed, 22 Mar 2006 20:04:00 -0000 [thread overview]
Message-ID: <y0mk6amdz4x.fsf@ton.toronto.redhat.com> (raw)
In-Reply-To: <CBDB88BFD06F7F408399DBCF8776B3DC06BC084A@scsmsx403.amr.corp.intel.com>
joshua wrote:
> [...]
> > If they are started by default, where exactly are they running?
> > Beginning of begin probe? End of begin probe?
>
> I think the perfmon setup needs to happen before all begin probes, so
> that the handle can be accessed within begin probes. [...]
How important would that be? At this time, we don't provide any
ordering guarantees amongst begin/end probes. If a begin probe would
have to manipulate the handle, why not put that right into the
perfctr.*.setup probe directly?
> A side note about handles [...] especially being able to
> dynamically enable/disable kprobes and timers.
Actual disarming of these kinds of probes is heavy-weight and may not
be safely done from within the confines of some generic
interrupt-disabled atomic probe handler. For the perfctr case, we may
just directly poke at registers.
Programmatic control of swaths of probes is an interesting problem
though.
- FChE
next prev parent reply other threads:[~2006-03-22 20:04 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-22 19:09 Stone, Joshua I
2006-03-22 20:04 ` Frank Ch. Eigler [this message]
-- strict thread matches above, loose matches on Subject: below --
2006-03-23 17:09 Stone, Joshua I
2006-03-22 23:46 Stone, Joshua I
2006-03-23 12:54 ` Maynard Johnson
2006-03-23 14:46 ` William Cohen
2006-03-22 23:23 Stone, Joshua I
2006-03-15 16:24 William Cohen
2006-03-15 22:34 ` Frank Ch. Eigler
2006-03-17 16:20 ` William Cohen
2006-03-17 17:10 ` Bill Rugolsky Jr.
2006-03-17 17:34 ` Frank Ch. Eigler
2006-03-17 20:26 ` William Cohen
2006-03-20 17:27 ` Frank Ch. Eigler
2006-03-22 3:34 ` Maynard Johnson
2006-03-22 18:02 ` William Cohen
2006-03-22 22:16 ` Maynard Johnson
2006-03-22 18:30 ` Frank Ch. Eigler
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