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RE: [cobalt-users] Qube 2 disk performance [long]
- Subject: RE: [cobalt-users] Qube 2 disk performance [long]
- From: Colin Smith <colin@xxxxxxxxxxxxxxxxxxxx>
- Date: Mon Jun 26 12:26:34 2000
On Fri, 23 Jun 2000, Smith Colin-WCCS07 wrote:
> > -----Original Message-----
> > From: Pierre Chopot [mailto:pierre.chopot@xxxxxxxxxxx]
> > Sent: 23 June 2000 09:23
> > To: cobalt-users@xxxxxxxxxxxxxxx
> > Subject: Re: [cobalt-users] Qube 2 disk performance
[snip]
> I can't remember all the hdparm information off the top of my head. I'll
> post more from home.
One thing about hdparm. The man page mentions several times that massive
filesystem corruption is possible with inappropriate settings so you have
been warned.
hdparm -Tt /dev/hda - Benchmark stats.
hdparm -I /dev/hda - Drive info.
hdparm -v /dev/hda - Current DMA/IO etc settings
My Qube has a Quantum Fireball 4Gb drive and 256Mb of RAM. Here are some
test with various settings:
-------------------------------------------------------------------------
Start vanilla:
hdparm -v /dev/hda
/dev/hda:
multcount = 0 (off)
I/O support = 0 (default 16-bit)
unmaskirq = 0 (off)
using_dma = 0 (off)
keepsettings = 1 (on)
nowerr = 0 (off)
readonly = 0 (off)
readahead = 0 (off)
geometry = 14848/9/63, sectors = 8418816, start = 0
Results:
time hdparm -Tt /dev/hda
/dev/hda:
Timing buffer-cache reads: 32 MB in 1.30 seconds =24.62 MB/sec
Timing buffered disk reads: 16 MB in 9.76 seconds = 1.64 MB/sec
0.07user 10.22system 0:20.01elapsed 51%CPU (0avgtext+0avgdata
0maxresident)k
0inputs+0outputs (620major+523minor)pagefaults 0swaps
-------------------------------------------------------------------------
Turn multicount on:
hdparm -v /dev/hda
/dev/hda:
multcount = 16 (on)
I/O support = 0 (default 16-bit)
unmaskirq = 0 (off)
using_dma = 0 (off)
keepsettings = 1 (on)
nowerr = 0 (off)
readonly = 0 (off)
readahead = 0 (off)
geometry = 14848/9/63, sectors = 8418816, start = 0
Results:
time hdparm -Tt /dev/hda
/dev/hda:
Timing buffer-cache reads: 32 MB in 1.29 seconds =24.81 MB/sec
Timing buffered disk reads: 16 MB in 7.62 seconds = 2.10 MB/sec
0.-22user 9.94system 0:17.86elapsed 54%CPU (0avgtext+0avgdata
0maxresident)k
0inputs+0outputs (620major+523minor)pagefaults 0swaps
-------------------------------------------------------------------------
Turn 32bit I/O on:
hdparm -v /dev/hda
/dev/hda:
multcount = 16 (on)
I/O support = 1 (32-bit)
unmaskirq = 0 (off)
using_dma = 0 (off)
keepsettings = 0 (off)
nowerr = 0 (off)
readonly = 0 (off)
readahead = 0 (off)
geometry = 14848/9/63, sectors = 8418816, start = 0
Results:
time hdparm -Tt /dev/hda
/dev/hda:
Timing buffer-cache reads: 32 MB in 1.30 seconds =24.62 MB/sec
Timing buffered disk reads: 16 MB in 6.27 seconds = 2.55 MB/sec
0.-11user 8.47system 0:16.47elapsed 50%CPU (0avgtext+0avgdata
0maxresident)k
0inputs+0outputs (620major+523minor)pagefaults 0swaps
-------------------------------------------------------------------------
Turn unmask IRQ on:
hdparm -v /dev/hda
/dev/hda:
multcount = 16 (on)
I/O support = 1 (32-bit)
unmaskirq = 1 (on)
using_dma = 0 (off)
keepsettings = 0 (off)
nowerr = 0 (off)
readonly = 0 (off)
readahead = 0 (off)
geometry = 14848/9/63, sectors = 8418816, start = 0
Results:
time hdparm -Tt /dev/hda
/dev/hda:
Timing buffer-cache reads: 32 MB in 1.31 seconds =24.43 MB/sec
Timing buffered disk reads: 16 MB in 7.65 seconds = 2.09 MB/sec
0.12user 9.52system 0:17.74elapsed 54%CPU (0avgtext+0avgdata
0maxresident)k
0inputs+0outputs (620major+523minor)pagefaults 0swaps
Think I'll turn this one back off.
-------------------------------------------------------------------------
Turn DMA on:
hdparm -v /dev/hda
/dev/hda:
multcount = 16 (on)
I/O support = 1 (32-bit)
unmaskirq = 0 (off)
using_dma = 1 (on)
keepsettings = 0 (off)
nowerr = 0 (off)
readonly = 0 (off)
readahead = 0 (off)
geometry = 14848/9/63, sectors = 8418816, start = 0
Results:
time hdparm -Tt /dev/hda
/dev/hda:
Timing buffer-cache reads: 32 MB in 1.31 seconds =24.43 MB/sec
Timing buffered disk reads: 16 MB in 5.85 seconds = 2.74 MB/sec
0.12user 2.64system 0:15.94elapsed 17%CPU (0avgtext+0avgdata
0maxresident)k
0inputs+0outputs (620major+523minor)pagefaults 0swaps
-------------------------------------------------------------------------
In conclusion:
Setting Read(Mb/s) CPU usage%
Vanilla 1.64 54
Multiblock 2.10 54
32bit I/O 2.55 50
IRQ unmask 2.09 54
DMA on 2.74 17
Note: Unmasking the IRQ may only be useful once DMA is enabled and would
only be useful to other processes anyway.
Well. Looks to me like the CPU utilisation can be reduced significantly
and the I/O can be increased at the same time. Lose your warranty I'll bet
though. It's also possible to set a spin down time on the drive. The same
way laptops can. This should reduce the power required but may reduce the
life of the drive. Anyone know about this?
--