Date: Sun, 18 Jul 2010 15:23:38 -0500 From: Dan Nelson <dnelson@allantgroup.com> To: Doug Barton <dougb@freebsd.org> Cc: Kostik Belousov <kostikbel@gmail.com>, freebsd-current@freebsd.org, Rui Paulo <rpaulo@freebsd.org> Subject: Re: Why is intr taking up so much cpu? Message-ID: <20100718202338.GI5485@dan.emsphone.com> In-Reply-To: <4C435CBE.50500@FreeBSD.org> References: <A81B337F-5932-44B1-BDB4-D9DD36332A16@lavabit.com> <alpine.BSF.2.00.1007171103060.1546@qbhto.arg> <F653FF83-D9CF-42A2-AE9A-B8F914090065@FreeBSD.org> <alpine.BSF.2.00.1007171208010.1538@qbhto.arg> <20100717192128.GM2381@deviant.kiev.zoral.com.ua> <alpine.BSF.2.00.1007180113370.1707@qbhto.arg> <20100718103003.GO2381@deviant.kiev.zoral.com.ua> <4C43541C.3060101@FreeBSD.org> <20100718194109.GU2381@deviant.kiev.zoral.com.ua> <4C435CBE.50500@FreeBSD.org>
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In the last episode (Jul 18), Doug Barton said:
> On 07/18/10 12:41, Kostik Belousov wrote:
> > When intr time starts accumulating again, try to do
> > "procstat -kk <intr process pid>" and correlate the clock thread tid
> > with the backtrace. Might be, it helps to guess what callouts are eating
> > the CPU.
>
> Will do, thanks!
You can also use dtrace to get a count of callouts and their time spent.
Run this for a few seconds then hit ^C:
#! /usr/sbin/dtrace -s
/* #pragma D option quiet */
callout_execute:::callout_start
{
this->start = timestamp;
}
callout_execute:::callout_end
{
this->end = timestamp;
/* printf("%a %d\n",args[0]->c_func, this->end - this->start); */
@times[args[0]->c_func] = quantize(this->end - this->start);
/* @times[args[0]->c_func] = lquantize(this->end - this->start,0,300000,10000); */
@counts[args[0]->c_func] = count();
}
END
{
printa("%a %@u\n",@times);
printa("%a %@u\n",@counts);
}
--
Dan Nelson
dnelson@allantgroup.com
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