Re: Linux Software RAID 5 Performance Optimizations: 2.6.19.1: (211MB/s read & 195MB/s write)

[Justin Piszcz <jpiszcz@lucidpixels.com>]

On Sat, 13 Jan 2007, Al Boldi wrote:

> Justin Piszcz wrote:
> > On Sat, 13 Jan 2007, Al Boldi wrote:
> > > Justin Piszcz wrote:
> > > > Btw, max sectors did improve my performance a little bit but
> > > > stripe_cache+read_ahead were the main optimizations that made
> > > > everything go faster by about ~1.5x.   I have individual bonnie++
> > > > benchmarks of [only] the max_sector_kb tests as well, it improved the
> > > > times from 8min/bonnie run -> 7min 11 seconds or so, see below and
> > > > then after that is what you requested.
> > >
> > > Can you repeat with /dev/sda only?
> >
> > For sda-- (is a 74GB raptor only)-- but ok.
> 
> Do you get the same results for the 150GB-raptor on sd{e,g,i,k}?
> 
> > # uptime
> >  16:25:38 up 1 min,  3 users,  load average: 0.23, 0.14, 0.05
> > # cat /sys/block/sda/queue/max_sectors_kb
> > 512
> > # echo 3 > /proc/sys/vm/drop_caches
> > # dd if=/dev/sda of=/dev/null bs=1M count=10240
> > 10240+0 records in
> > 10240+0 records out
> > 10737418240 bytes (11 GB) copied, 150.891 seconds, 71.2 MB/s
> > # echo 192 > /sys/block/sda/queue/max_sectors_kb
> > # echo 3 > /proc/sys/vm/drop_caches
> > # dd if=/dev/sda of=/dev/null bs=1M count=10240
> > 10240+0 records in
> > 10240+0 records out
> > 10737418240 bytes (11 GB) copied, 150.192 seconds, 71.5 MB/s
> > # echo 128 > /sys/block/sda/queue/max_sectors_kb
> > # echo 3 > /proc/sys/vm/drop_caches
> > # dd if=/dev/sda of=/dev/null bs=1M count=10240
> > 10240+0 records in
> > 10240+0 records out
> > 10737418240 bytes (11 GB) copied, 150.15 seconds, 71.5 MB/s
> >
> >
> > Does this show anything useful?
> 
> Probably a latency issue.  md is highly latency sensitive.
> 
> What CPU type/speed do you have?  Bootlog/dmesg?
> 
> 
> Thanks!
> 
> --
> Al
> 
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> What CPU type/speed do you have?  Bootlog/dmesg?
Core Duo E6300

The speed is great since I have tweaked the various settings..
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