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Wrong checksumming function chosen

DISCUSSION Sebastian Schäfer 2 participants 2 messages Sep 22, 2002 MD RAID

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Hi!

It seems as my computer (Athlon XP 2000+) chooses the wrong checksumming function.

The kernel output is as follows:

raid5: measuring checksumming speed

   8regs     :  2564.000 MB/sec
   32regs    :  2260.000 MB/sec
   pIII_sse  :  4748.400 MB/sec
   pII_mmx   :  3921.200 MB/sec
   p5_mmx    :  5022.400 MB/sec

raid5: using function: pIII_sse (4748.400 MB/sec)

I hope I can help the developers with this piece of information. And I also hope I mailed at the right address.

Greets,

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Sebastian Schäfer
E-Mail: [email protected] || http://www.uliweb.de
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#1 lore raw
Quoted 13 lines · On Sunday September 22, [email protected] wrote:

Hi!

It seems as my computer (Athlon XP 2000+) chooses the wrong checksumming function.

The kernel output is as follows:

raid5: measuring checksumming speed

   8regs     :  2564.000 MB/sec
   32regs    :  2260.000 MB/sec
   pIII_sse  :  4748.400 MB/sec
   pII_mmx   :  3921.200 MB/sec
   p5_mmx    :  5022.400 MB/sec
Quoted 4 lines

raid5: using function: pIII_sse (4748.400 MB/sec)

I hope I can help the developers with this piece of information. And I also hope I mailed at the right address.

The only problem here is that the message is misleading.

pIII_sse is deliberately chosen despite appearing not to be so fast because it avoid the level-1 cache which is appropriate for this data which is only used by the CPU once.

NeilBrown

Quoted 9 lines

Greets,

Signature · 6 lines
Sebastian Schäfer
E-Mail: [email protected] || http://www.uliweb.de
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