lkml.org 
[lkml]   [1999]   [Jun]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectPoor SCSI // reading using 2.2.10-ac4 SMP

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

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:52    [from the cache]
©2003-2011 Jasper Spaans