Date: Mon, 15 Feb 2010 06:53:20 -0800 (PST) From: Fernando Gleiser <fergleiser@yahoo.com> To: Shrikanth Kamath <shrikanth07@gmail.com>, freebsd-hackers@freebsd.org Subject: Re: Ktrace'ing kernel threads Message-ID: <909320.96307.qm@web31703.mail.mud.yahoo.com> In-Reply-To: <291941b81002150321w7b0479beo1c6fec39ef6a7922@mail.gmail.com> References: <291941b81002150321w7b0479beo1c6fec39ef6a7922@mail.gmail.com>
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----- Original Message ----
> From: Shrikanth Kamath <shrikanth07@gmail.com>
> To: freebsd-hackers@freebsd.org
> Sent: Mon, February 15, 2010 8:21:40 AM
> Subject: Ktrace'ing kernel threads
>
> Can ktrace trace another kernel thread which has roughly the semantics as
> below, right now it
> does not hit any of the designated interesting points that ktrace is built
> for, but what if I could define those,
> will ktrace still allow tracing another kernel thread?
Yo can do that easily with dtrace
#!/usr/sbin/dtrace -s
fbt::build_msg:entry
{
printf("%d\n", timestamp)
}
fbt::build_msg:return
{
printf("%d\n", timestamp)
}
or if you want to get an histogram of the call time distributions:
fbt::build_msg:entry
{
self->ts=timestamp;
}
fbt::build_msg:return
{
@[probefunc]=quantize(timestamp - self->ts);
}
Those are from the top of my head, I don't have a FreeBSD system at hand to test them, but I hope you'll get the idea
Fer
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