On Tue, 15 Feb 2005, Magnus Hagander wrote:
> Run:
> hdparm -I /dev/hda
>
> If you get a line like:
> Commands/features:
> Enabled Supported:
> * READ BUFFER cmd
> * WRITE BUFFER cmd
> * Host Protected Area feature set
> * Look-ahead
> * Write cache
> ...
> (last line is what matters here)
> you have write cacheing enabled.
Thanks. Ok, really I have it enabled (fortunately :)
>
> To turn it of, run
> hdparm -W0 /dev/hda
Done. Now it is disabled.
>
> Not sure if you need to reboot, I don'tt hink so. Then re-run the
> benchmark on linux.
No, under Linux reboot makes nothing (it is completely dynamical system).
Now I have
/usr/local/pgsql/bin:14>pgbench -c 1 -t 500
starting vacuum...end.
transaction type: TPC-B (sort of)
scaling factor: 1
number of clients: 1
number of transactions per client: 500
number of transactions actually processed: 500/500
tps = 89.528064 (including connections establishing)
tps = 89.560730 (excluding connections establishing)
It is about 9 times slower. But again 4 times faster then under Windows.
After
root@390x:/e# hdparm -W1 /dev/hda
/dev/hda: setting drive write-caching to 1 (on)
/usr/local/pgsql/bin:24>pgbench -c 1 -t 500
starting vacuum...end.
transaction type: TPC-B (sort of)
scaling factor: 1
number of clients: 1
number of transactions per client: 500
number of transactions actually processed: 500/500
tps = 846.189777 (including connections establishing)
tps = 849.481986 (excluding connections establishing)
Regards,
E.R.
_________________________________________________________________________
Evgeny Rodichev Sternberg Astronomical Institute
email: er@sai.msu.su Moscow State University
Phone: 007 (095) 939 2383
Fax: 007 (095) 932 8841 http://www.sai.msu.su/~er