From: Nick Piggin <nickpiggin@yahoo.com.au>
To: linux-ia64@vger.kernel.org
Subject: Re: Volanomark regress on ia64
Date: Sun, 18 Sep 2005 10:56:31 +0000 [thread overview]
Message-ID: <432D47DF.30706@yahoo.com.au> (raw)
In-Reply-To: <200509160040.j8G0eFg06734@unix-os.sc.intel.com>
Chen, Kenneth W wrote:
> Take a look at http://kernel-perf.sourceforge.net/results.machine_id&.html
>
> First chart with volanomark benchmark. It took ~ 11% performance regression
> on 2.6.13-git9 and 2.6.14-rc1.
>
> It is not those two particular kernel version have the problem per se. It
> would've shown on 2.6.13-rc1 when default hz rate was switched to 250. Last
> week, I happened to audit the system and made the hz switch and the problem
> showed up.
>
> Hz\x1000 cpu idle is about 54%, the raw throughput is 74935 msgs/sec
> Hz%0 cpu idle is about 58%, the raw throughput is 67246 msgs/sec
>
> I think it has something to do with the scheduler load balance. While I'm
> looking into schedstat and etc. Posting here for everyone to pour over the
> issue.
>
> vmstat/readprofle/schedstat result with 1K hz and 250 hz attached.
>
Hi Ken,
Made any progress yet?
It looks like the problem is confined to ia64? Are the x86-64 machines
also running with HZ set to 250?
I would look at differences between SD_CPU_INIT for ia64 versus the
generic definition. cache_hot_time and cache_nice_tries by the looks,
both those could cause increased idle time.
Nick
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
next prev parent reply other threads:[~2005-09-18 10:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-16 0:40 Volanomark regress on ia64 Chen, Kenneth W
2005-09-18 10:56 ` Nick Piggin [this message]
2005-09-18 21:43 ` John Hawkes
2005-09-19 6:44 ` Chen, Kenneth W
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