Subject: Re: [linux-audio-dev] more numbers for multichannel playback
From: David Olofson (david_AT_gardena.net)
Date: Thu Apr 06 2000 - 08:58:44 EEST
On Thu, 06 Apr 2000, David Olofson wrote:
> I get around 30 MB/s from my 20 GB EIDE UDMA DiamondMax using FAT
> or FAT32 partitions under Windoze. A good, modern SCSI drive should be
> even faster.
>
> I'll do some test on ext2 partitions and see what I get...
Back.
Ran the test code on my DiamondMax, using a 200 MB file (filled with
white noise - no holes) and flushing the buffer cache before each
test. All tests done under Linux 2.2.13. The figures are the worst
cases I got over a few tests. Buffers of 1024 vs. 65536 bytes make no
significant difference.
ext2: 17 MB/s
FAT16: 19 MB/s
Note: The FAT16/ext2 difference could be because the partitions
aren't on the same area of the disk. (More sectors on outer tracks.)
Then again, the FAT16 partition occupies cylinders 784-1010 and the
ext2 partition occupies 1071-1153. I tried another ext2 partition at
523-783, and got 18 MB/s... (The drive has 2489 cylinders with this
mapping - the last 10 GB being my FAT32 HDR partition.)
hdparm -t /dev/hda gives 18 MB/s worst case, normally 18.8 MB/s.
The drive spec says about 31 MB/s max transfer rate for this drive,
and I get some 95% of that under Windoze when *writing*, but only
about 50% (ie slightly worse than the above) when reading. This is
very common - I've actually never seen an IDE drive that *doesn't*
behave this way. Not sure about SCSI, though.
//David
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