From: Rik van Riel <riel@redhat.com>
To: "Sergey Popov" <faijeya@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: General slowness with using 64Gb HIGHMEM option on 32-bit kernel
Date: Fri, 28 Sep 2007 14:03:22 -0400 [thread overview]
Message-ID: <20070928140322.5fbbde5d@bree.surriel.com> (raw)
In-Reply-To: <dd4eba420709281057x69a9366cp8fc755782efea656@mail.gmail.com>
On Fri, 28 Sep 2007 21:57:55 +0400
"Sergey Popov" <faijeya@gmail.com> wrote:
> Ok, I found a palliative.
>
> Now I'm working with "mem=6770M" option, that gives me 6072MB RAM (of
> 6144 total).
> Interesting, that if you choose too much, like "mem=6800M", system
> behaviour is exactly the same as without any options.
>
> Can it be that kernel incorrectly sets amount of memory to use so such
> a situation occurs?
Maybe the BIOS marks the top megabytes of memory as
uncacheable, which makes accesses ridiculously slow.
Cat /proc/mtrr to check.
--
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it." - Brian W. Kernighan
next prev parent reply other threads:[~2007-09-28 18:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-28 17:15 General slowness with using 64Gb HIGHMEM option on 32-bit kernel Sergey Popov
2007-09-28 3:22 ` Nick Piggin
2007-09-28 17:46 ` Chuck Ebbert
2007-09-28 17:57 ` Sergey Popov
2007-09-28 18:03 ` Rik van Riel [this message]
[not found] <fa.mssrRT/qBOVwvrr2k/d2or6ggOo@ifi.uio.no>
2007-09-28 23:40 ` Robert Hancock
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