Messages in this thread | | | Date | Wed, 30 Jun 1999 12:26:21 +0200 | From | Thierry Danis <> | Subject | Poor SCSI // reading using 2.2.10-ac4 SMP |
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Hello,
I have run iozone locally on my new 18 Go hard disk to check performance. The Linux machine is a PII 400/128 Mo/SMP/Tekram 390F.
I have quite good results with only one iozone : 17+ Mo/s writing, 15+ Mo/s reading.
Now, I can see really bad performance with 3 iozones running : 17+ Mo/s (cumulated) writing, and 2,7 Mo/s (cumulated) reading. At the time of reading, both CPU load is nearly null.
If I use a UP kernel (2.2.10-ac4 or 2.2.5) I have 8+ Mo/s reading, which can be explained (I guess) due to heads movements and seek times.
So, it seems that SMP has big trouble when parrallelizing readings (maybe a problem with SCSI, I do not know, since I have no IDE on the SMP box).
A+, -- Thierry Danis Poste : 53 53 danis@spmo.sagem.fr
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