On Sat, 28 Aug 2010 19:50:24 +0400 Ilya Bakulin <webmas...@kibab.com> wrote:
> On Sat, 28 Aug 2010 13:09:12 +0400
> Ilya Bakulin <webmas...@kibab.com> wrote:
>
> > Right now I'm running phybs -w /dev/ad7p1
>
> Well, phybs finished.
I feel like a flooder today :-)
I've created gnop provider on top of the existing ad7p1:
kibab-desktop# gnop create -o 512 -S 4096 ad7p1
So, ad7p1.nop is shifted by 512 bytes and resides right on the beginning of the
physical sector. And it has 4096 "sector" size.
Running phybs:
kibab-desktop# ./phybs -w /dev/ad7p1.nop
count size offset step msec tps kBps
16384 8192 0 32768 11222 311 11679
16384 8192 4096 32768 11836 295 11073
8192 16384 0 65536 17432 223 7518
8192 16384 4096 65536 18148 214 7222
8192 16384 8192 65536 17811 218 7358
4096 32768 0 131072 20800 196 6301
4096 32768 4096 131072 12651 323 10360
4096 32768 8192 131072 15040 272 8714
4096 32768 16384 131072 15970 256 8206
2048 65536 0 262144 8005 255 16372
2048 65536 4096 262144 8152 251 16077
2048 65536 8192 262144 7636 268 17163
2048 65536 16384 262144 9372 218 13985
2048 65536 32768 262144 9356 218 14008
For some reason, phybs begins with sector size 8192... I expected it to begin
with 4096...
Let's force 4096:
kibab-desktop# ./phybs -l 4096 -w /dev/ad7p1.nop
count size offset step msec tps kBps
32768 4096 0 16384 15621 173 8390
16384 8192 0 32768 11331 308 11566
16384 8192 4096 32768 13045 268 10047
8192 16384 0 65536 28344 137 4624
8192 16384 4096 65536 22540 172 5815
8192 16384 8192 65536 24530 158 5343
4096 32768 0 131072 16221 252 8080
4096 32768 4096 131072 13986 292 9371
4096 32768 8192 131072 14736 277 8894
4096 32768 16384 131072 14370 285 9121
Perfomance is excellent!
Notice, that for two subsequent phybs invocations there is big difference in
timings for the same parameters.
For example, writing with block size=16384 at offset=0:
1st run: 7518 kBps,
2nd run: 4624 kBps.
This tells us that we cannot really compare these numbers with each other. The
most important, however, is that they are significantly higher than misaligned
writes. So using gnop is really a good solution.
--
Regards,
Ilya Bakulin
http://kibab.com
xmpp://kibab...@jabber.ru
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