From: "Martin J. Bligh" <Martin.Bligh@us.ibm.com>
To: Linus Torvalds <torvalds@transmeta.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Andrew Theurer <habanero@us.ibm.com>
Subject: Re: [PATCH] NUMA-Q disable irqbalance
Date: Tue, 13 Aug 2002 13:42:12 -0700 [thread overview]
Message-ID: <2016010000.1029271332@flay> (raw)
In-Reply-To: <Pine.LNX.4.44.0208131332440.1265-100000@home.transmeta.com>
>> On a collection of networking workloads the P4 is about 5% better
>> performing with the irq balancer off.
>
> Hmm. And I could _feel_ how my dual HT P4 was slow before the irq issues
> were fixed.
>
> Now, there have been other changes too - like the scheduler (and my
> current P4 has a different SCSI interface), but I dunno. The thing I
> attributed the improvements in interactive feel was the fact that the work
> got balanced out more sanely.
Was that before or after you changed HZ to 1000? I *think* that increased
the frequency of IO-APIC reprogramming by a factor of 10, though I might
be misreading the code. If it does depend on HZ, I think that's bad.
People in our benchmarking group (Andrew, cc'ed) have told me that
reducing the frequency of IO-APIC reprogramming by a factor of 20 or so
improves performance greatly - don't know what HZ that was at, but the
whole thing seems a little overenthusiastic to me.
M.
next prev parent reply other threads:[~2002-08-13 20:42 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-08-05 23:51 [PATCH] NUMA-Q disable irqbalance Martin J. Bligh
2002-08-13 16:13 ` Martin J. Bligh
2002-08-13 16:41 ` Linus Torvalds
2002-08-13 16:57 ` Alan Cox
2002-08-13 17:24 ` Martin J. Bligh
2002-08-13 17:38 ` Alan Cox
2002-08-13 17:14 ` Martin J. Bligh
2002-08-13 17:24 ` Linus Torvalds
2002-08-13 18:02 ` Martin J. Bligh
2002-08-13 18:20 ` Linus Torvalds
2002-08-13 18:58 ` Martin J. Bligh
2002-08-13 19:22 ` Linus Torvalds
2002-08-13 20:04 ` Martin J. Bligh
2002-08-13 20:22 ` Linus Torvalds
2002-08-14 5:52 ` Martin J. Bligh
2002-08-14 10:10 ` Jos Hulzink
2002-08-14 11:12 ` David Lang
2002-08-13 20:22 ` Alan Cox
2002-08-13 20:35 ` Linus Torvalds
2002-08-13 20:34 ` Alan Cox
2002-08-13 20:42 ` Martin J. Bligh [this message]
2002-08-13 21:24 ` Linus Torvalds
2002-08-13 22:29 ` Andrew Theurer
2002-08-13 23:30 ` Andrea Arcangeli
2002-08-14 21:16 ` James Cleverdon
2002-08-23 2:31 ` [PATCH] 2.5.31 Summit NUMA patch with dynamic IRQ balancing James Cleverdon
[not found] ` <20020813233007.GV14394-YO0K3UtdbwQZxi9Dt0/nrQC/G2K4zDHf@public.gmane.org>
2002-08-23 2:31 ` James Cleverdon
2002-08-20 0:49 ` [PATCH] NUMA-Q disable irqbalance Dave Hansen
2002-08-13 22:08 ` Rik van Riel
2002-08-13 22:14 ` Rik van Riel
2002-08-14 14:49 ` Linus Torvalds
2002-08-14 15:19 ` Rik van Riel
2002-08-24 12:19 ` Zwane Mwaikambo
2002-08-27 1:23 ` James Cleverdon
2002-08-27 7:46 ` Zwane Mwaikambo
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