linux-kernel - Re: [PATCH 0/5] Proper kernel irq time reporting -v0

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Message-ID: <4CC07784.4090805@digium.com>
Date:	Thu, 21 Oct 2010 12:25:24 -0500
From:	Shaun Ruffell <sruffell@...ium.com>
To:	Venkatesh Pallipadi <venki@...gle.com>
CC:	Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...e.hu>,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Balbir Singh <balbir@...ux.vnet.ibm.com>,
	Martin Schwidefsky <schwidefsky@...ibm.com>,
	linux-kernel@...r.kernel.org, Paul Turner <pjt@...gle.com>,
	Eric Dumazet <eric.dumazet@...il.com>,
	Yong Zhang <yong.zhang0@...il.com>
Subject: Re: [PATCH 0/5] Proper kernel irq time reporting -v0

On 10/20/2010 05:48 PM, Venkatesh Pallipadi wrote:
> This is part 2 of
> "Proper kernel irq time accounting -v4"
> http://lkml.indiana.edu/hypermail//linux/kernel/1010.0/01175.html
> 
> and applies over those changes.
> 

I applied both sets on top of 2.6.36 and tested on x86 32-bit and 64-bit
machines with some telephony cards that interrupt at a 1000Hz rate.  The
time reported in top matched the expected value as measured with the
function graph tracer.  i.e, if /sys/kernel/debug/tracing/trace
indicated that the interrupt handler was averaging 13us, then top was
reporting 1.3% CPU time.  I changed the smp_affinity and the "hi" time
moved around as I would have expected.  I also scheduled work items on
all the CPUs that just disable interrupt and spin for a selectable
period.  Scheduling 100ms of non-interruptible delay at 1 second
intervals resulted in 10% time in "hi" as expected.

Hopefully I can check it out on a Powermac G3 B&W next week sometime,
but FWIW:

Tested-by: Shaun Ruffell <sruffell@...ium.com>
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