Re: [PATCH] SMP race in ext2 - metadata corruption.

From: Rogier Wolff (R.E.Wolff@BitWizard.nl)
Date: Fri May 04 2001 - 06:40:54 EST


Linus Torvalds wrote:
>
> On Thu, 3 May 2001, Alan Cox wrote:
> > Ditto for some CD based stuff. You burn the important binaries to the front
> > of the CD, then at boot dd 64Mb to /dev/null to prime the libraries and
> > avoid a lot of seeking during boot up from the CD-ROM.
> >
> > However I could do that from an initrd before mounting
>
> Ehh. Doing that would be extremely stupid, and would slow down your boot
> and nothing more.

Ehhh, Linus, Linearly reading my harddisk goes at 26Mb per second. By
analyzing my boot process I determine that 50M of my disk is used
during boot. I can then reshuffle my disk to have that 50M of data at
the beginning and reading all that into 50M of cache, I can save
thousands of 10ms seeks. Boot time would go from several tens of
seconds to 2 seconds worth of DISK IO plus several seconds of pure CPU
time.

This doesn't work if I don't have the memory to cache 50M of
disk-blocks.

Is this simply: Don't try this then?

                                Roger.

-- 
** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 **
*-- BitWizard writes Linux device drivers for any device you may have! --*
* There are old pilots, and there are bold pilots. 
* There are also old, bald pilots. 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Mon May 07 2001 - 21:00:19 EST