From: Dave Hansen <haveblue@us.ibm.com>
To: "Martin J. Bligh" <mbligh@aracnet.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@digeo.com>,
William Lee Irwin III <wli@holomorphy.com>
Subject: Re: Overhead of highpte
Date: 03 Jul 2003 19:34:19 -0700 [thread overview]
Message-ID: <1057286058.11027.106.camel@nighthawk> (raw)
In-Reply-To: <574790000.1057186404@flay>
On Wed, 2003-07-02 at 15:53, Martin J. Bligh wrote:
> Some people were saying they couldn't see an overhead with highpte.
> Seems pretty obvious to me still. It should help *more* on the NUMA
> box, as PTEs become node-local.
>
> The kmap_atomic is, of course, perfectly understandable. The increase
> in the rmap functions is a bit of a mystery to me.
>
> M.
>
> Kernbench: (make -j vmlinux, maximal tasks)
> Elapsed System User CPU
> 2.5.73-mm3 45.38 114.91 565.81 1497.75
> 2.5.73-mm3-highpte 46.54 130.41 566.84 1498.00
OK, let's add to the mystery. Here's my run, on virtually the same
hardware except, I don't do a bzImage. bzImage is pretty useless
because I don't want to benchmark gzip, so I just do vmlinux. My times
should be _faster_ than yours, right?
Elapsed: User: System: CPU:
2.5.73-mjb2 77.008s 937.756s 90s 1334%
2.5.73-mjb2-highpte 76.756s 935.464s 93.116s 1339%
Yeah, system time goes up. Something funky is going on. We should have
the same machines, except that I have twice the RAM, right? What kind
of fs are you doing your tests on? I'm doing ramfs.
--
Dave Hansen
haveblue@us.ibm.com
next prev parent reply other threads:[~2003-07-04 2:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-07-02 22:53 Overhead of highpte Martin J. Bligh
2003-07-02 23:15 ` William Lee Irwin III
2003-07-03 0:02 ` William Lee Irwin III
2003-07-04 2:34 ` Dave Hansen [this message]
2003-07-04 2:46 ` Martin J. Bligh
2003-07-04 2:54 ` Dave Hansen
2003-07-04 3:53 ` Overhead of highpte (or not :) Dave Hansen
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