Re: General slowness with using 64Gb HIGHMEM option on 32-bit kernel
From: Nick Piggin
Date: Fri Sep 28 2007 - 17:46:24 EST
On Saturday 29 September 2007 03:15, Sergey Popov wrote:
> Short description: after recompiling 32-bit kernel with 64Gb highmem
> support and rebooting into it, OS started working very much slower
> then before.
> Specifications: Intel Core 2 Duo E6600@2,4Ghz on Intel i965Q-based
> motherboard. 6Gb of DDR2 RAM, 2x1Gb+2x2Gb, dual-channel.
> Vector Linux 5.8 (Slackware Linux 11-based), 184.108.40.206 kernel.
> Long description: after recompiling 32-bit 220.127.116.11 kernel with 64Gb
> highmem option and rebooting into it, booting process froze on udevd.
> After booting up from CD and disabling rc.udev, system started, but
> it's work after rc.M script sarted was 5-10 times slower then usual.
> top showed, that processes are taking much more CPU% time then usual.
> I tried downloading the newest stable kernel - 18.104.22.168 - hoping, that
> it would solve the problem. I downloaded it, booted from CD, and
> compiled it with 64Gb highmem support. I felt some speed improvement,
> but if on 22.214.171.124 machine performed like P166, now it is working like
> I've found a similar problem, described on lkml -
> http://lkml.org/lkml/2007/5/30/5 . But, unfortunately, it is x86_64
> related and contains no clues for me.
It's most likely the MTRR problem that Rik mentioned.
> Moving to 64-bit distro is rather unpleasant - as there is an option
> in 32-bit kernel, it should work ;) .
If you have a gcc that can compile 64-bit code, then I found it was as
simple as doing a 'make ARCH=x86_64' and building the kernel with 32-bit
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/