From: "fche at redhat dot com" <sourceware-bugzilla@sourceware.org>
To: systemtap@sources.redhat.com
Subject: [Bug runtime/5194] IO problem on begin/end probes
Date: Thu, 18 Oct 2007 15:19:00 -0000 [thread overview]
Message-ID: <20071018151900.31080.qmail@sourceware.org> (raw)
In-Reply-To: <20071018140048.5194.hunt@redhat.com>
------- Additional Comments From fche at redhat dot com 2007-10-18 15:18 -------
(In reply to comment #3)
> calling a sleeping function in a begin probe.
That remains invalid, even with the slight relaxing we did earlier.
> If the begin/end probe does sleep or get interrupted, it might
> not get the same cpu when it resumes,
Interrupts do not cause a reschedule or cpu reassingnment if
preemption was blocked (as it is).
> which means the output buffer will change without the
> previous buffer getting flushed and data will be lost.
If this is the limit of what can happen when a user schemes to call
a sleeping function (which can only happen in "-g" mode anyway), then
this problem is a minor one.
> IIRC, one of the reasons we enabled preemption was to handle situations where
> large arrays are dumped during end probes.
That was only a side-effect. We wanted to produce "long" reports, for "long"
meaning perhaps thousands of lines. It's not megabytes. With the status
quo, SMP machines may be able to keep up with even that.
--
http://sourceware.org/bugzilla/show_bug.cgi?id=5194
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next prev parent reply other threads:[~2007-10-18 15:19 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-18 14:01 [Bug runtime/5194] New: " hunt at redhat dot com
2007-10-18 14:10 ` [Bug runtime/5194] " fche at redhat dot com
2007-10-18 14:11 ` fche at redhat dot com
2007-10-18 14:25 ` hunt at redhat dot com
2007-10-18 15:19 ` fche at redhat dot com [this message]
2008-01-21 17:42 ` fche at redhat dot com
2008-01-21 17:56 ` hunt at redhat dot com
2008-01-21 18:13 ` [Bug runtime/5194] IO problem on begin/end probes; need fche at redhat dot com
2008-01-21 18:37 ` fche at redhat dot com
2008-01-29 16:40 ` fche at redhat dot com
2008-01-29 17:08 ` hunt at redhat dot com
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