[Stgt-devel] No LUN option in target.c

[Tomasz Chmielewski]

FUJITA Tomonori schrieb:
> On Mon, 26 Nov 2007 12:25:19 +0100
> Albert Pauw <albert.pauw at gmail.com> wrote:
> 
>> 2007/11/26-12:24:19 | STAT  | 3237 | v1.2.8 | /dev/sdb | Total read 
>> throughput: 827938.1B/s (0.79MB/s), IOPS 25.3/s.
>>
>> The patch didn't make a difference, sorry.
> 
> The performances in the configuration don't matter much, but I just
> run initiator and target on the same machine:
> 
> sens:/home/fujita# hdparm -t /dev/sdd
> 
> /dev/sdd:
>  Timing buffered disk reads:   20 MB in  3.15 seconds =   6.35 MB/sec

(...)

> sens:/home/fujita# hdparm -t /dev/sdd
> 
> /dev/sdd:
>  Timing buffered disk reads:  410 MB in  3.02 seconds = 135.55 MB/sec
> 
> 
> Seems that haparm isn't an appropriate tool to meature performance but
> not bad performances.

It is appropriate, when used appropriately.

If a block device is used (mounted, swap, md/dm etc.) it is also cached.


One should always clear the cache if wants to measure performance (on 
the target, on the initiator, or both, depending on where the block 
device is used; to be 100% sure, clear the cache on both target and 
initiator before each test):

echo 3 > /proc/sys/vm/drop_caches


-- 
Tomasz Chmielewski
http://wpkg.org