Re: [linux-audio-dev] Software RAID and disk throughput/latency issues

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Subject: Re: [linux-audio-dev] Software RAID and disk throughput/latency issues
From: rob_AT_mur.org.uk
Date: Mon Jan 21 2002 - 16:36:51 EET


Hi

re UDMA performance

Here is a quick test I did on an IBM 5400RPM drive connected to a
Promise Technology, Inc. 20267 (rev 02) (ata66 or ata100 not sure). I
think UDMA mode 2 is 33, but I could be completely wrong. It's
interesting that mode 4 is faster than mode 5. I know this isn't very
scientific, but it shows that even 5400 drives can benefit from ata66/100.
 
linux# hdparm -X66 /dev/hde

/dev/hde:
 setting xfermode to 66 (UltraDMA mode2)
linux# hdparm -tT /dev/hde

/dev/hde:
 Timing buffer-cache reads: 128 MB in 1.08 seconds =118.52 MB/sec
 Timing buffered disk reads: 64 MB in 3.15 seconds = 20.32 MB/sec
linux# hdparm -X67 /dev/hde

/dev/hde:
 setting xfermode to 67 (UltraDMA mode3)
linux# hdparm -tT /dev/hde

/dev/hde:
 Timing buffer-cache reads: 128 MB in 1.08 seconds =118.52 MB/sec
 Timing buffered disk reads: 64 MB in 2.60 seconds = 24.62 MB/sec
linux# hdparm -X68 /dev/hde

/dev/hde:
 setting xfermode to 68 (UltraDMA mode4)
linux# hdparm -tT /dev/hde

/dev/hde:
 Timing buffer-cache reads: 128 MB in 1.08 seconds =118.52 MB/sec
 Timing buffered disk reads: 64 MB in 2.18 seconds = 29.36 MB/sec
linux# hdparm -X69 /dev/hde

/dev/hde:
 setting xfermode to 69 (UltraDMA mode5)
linux# hdparm -tT /dev/hde

/dev/hde:
 Timing buffer-cache reads: 128 MB in 1.09 seconds =117.43 MB/sec
 Timing buffered disk reads: 64 MB in 2.33 seconds = 27.47 MB/sec
linux#

On another machine: A 7200 RPM drive connected to a via ata33
controler:

/dev/hdc:
 Timing buffer-cache reads: 128 MB in 0.79 seconds =162.03 MB/sec
 Timing buffered disk reads: 64 MB in 1.78 seconds = 35.96 MB/sec

Looks like I should move this drive to a faster controler.

Regards

-- 
Rob Murray


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