File System Performance

Ben Israel (ben@genesis-one.com)
Mon, 12 Nov 2001 08:54:57 -0500


My System:
Pentium III 800MHz
128M SDRAM
Aug 2001 MSC Linux
XFS File System

My Results:
hdparm /dev/hda

/dev/hda:
multcount = 0 (off)
I/O support = 0 (default 16-bit)
unmaskirq = 0 (off)
using_dma = 1 (on)
keepsettings = 0 (off)
nowerr = 0 (off)
readonly = 0 (off)
readahead = 8 (on)
geometry = 3739/255/63, sectors = 60074784, start = 0

hdparm -t /dev/hda

/dev/hda:
Timing buffered disk reads: 64 MB in 2.71 seconds = 23.62 MB/sec

time cp -r /usr/src/linux-2.4.6 tst

real 0m47.376s
user 0m0.180s
sys 0m2.710s

du -bs tst
144187392 tst

Actual Performance
2*144MB/48s=6MB/sec

Notes:
1) for consistent results; data size should exceed file cache.
2) cp reads and writes files: so 2*3MB/sec = 6MB/sec fileio on a 24MB/sec
drive

My Questions:
Is there a way of identifying what the file system is doing here?
Is there a way to improve it?
What tools are there to identify and time the raw disk io done by the file
system?

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