Messages in this thread | | | Date | Thu, 8 Jan 2004 15:34:16 -0800 (PST) | From | LKML <> | Subject | Odd speed problems with aic79xx drivers on RHEL |
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We have a Dual Xeon server with onboard aic79xx based controller, which is connected to a 16port SATA-SCSI RAID unit, which supports Ultra160.
When we first got the server, it was running RH9 with a custom kernel, and we were getting bonnie++ test results of 100MB/s read and write speed on the custom 2.4.21 based kernel(with aic79xx driver 1.3.x) while keeping a load average of approximatel 1.7.
Once we installed Redhat Enterprise Linux AS 3.0, with its 2.4.21-4.EL kernel, we've been getting write speed of 120MB/s, but read speed of only about 50MB/s. That's right, read is slower than write. I've tried upping the TCQ from the default of 32 to 253, and that decreased the read speed even further, down to 40MB/s.
We've tried putting back on the server vendor's custom kernel, but that kernel now seg faults whenever we run bonnie++.
I've tried recomping the Enterprise kernel with the latest aic79xx driver from Justin's site, with no change. Turning TCQ turned off, I was able to get 95MB/s read and write, but at a much higher load average of 2.9. Shouldn't enabling TCQ improve the speed? Any thoughts or suggestions on what to try next?
- John
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