On Thu, 5 Jul 2007, Bill Davidsen wrote:

Justin Piszcz wrote:

quoted

On Wed, 4 Jul 2007, Justin Piszcz wrote:

quoted

On Wed, 4 Jul 2007, Michael Tokarev wrote:

quoted

Tejun Heo wrote:

quoted

Hello,

Michael Tokarev wrote:

quoted

Well.  It looks like the results does not depend on the
elevator.  Originally I tried with deadline, and just
re-ran the test with noop (hence the long delay with
the answer) - changing linux elevator changes almost
nothing in the results - modulo some random "fluctuations".

I see.  Thanks for testing.

Here are actual results - the tests were still running when
I replied yesterday.

Again, this is Seagate ST3250620AS "desktop" drive, 7200RPM,
16Mb cache, 250Gb capacity.  The tests were performed with
queue depth = 64 (on mptsas), drive write cache is turned
off.

I found AS scheduler to be the premium and best for single-user 
performance.

You want speed? Use AS.

http://home.comcast.net/~jpiszcz/sched/cfq_vs_as_vs_deadline_vs_noop.html

Does not include noop-- tested the main three though, renamed :)

http://home.comcast.net/~jpiszcz/sched/cfq_vs_as_vs_deadline.html

And for the archives:

p34-cfq,15696M,77114.3,99,311683,55.3333,184947,38.6667,79842.7,99,524065,41.3333,634.033,0.333333,16:100000:16/64,1043.33,8.33333,4419.33,11.6667,2942,17.3333,1178,10.3333,4192.67,12.3333,2619.33,19 
p34-as,15696M,76202.3,99,443103,85,189716,34.6667,79552,99,507271,39.6667,607.067,0,16:100000:16/64,1153,10,13434,36,2769.67,16.3333,1201.67,10.6667,3951.33,12,2665.67,19 
p34-deadline,15696M,76933.3,98.6667,386852,72,183016,29.6667,79530.7,99,512082,39.6667,678.567,0,16:100000:16/64,1230.33,10.3333,12349,32.3333,2945,17.3333,1258,11,8183,22.3333,2867,20.3333 

I looked at these before, did you really run with a chunk size of just under 
16GB, or does "15696M" have some inobvious meaning?

-- 
Bill Davidsen [off-list ref]
 "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot

It says to use double your RAM, your RAM is 7848, so that is why I use 
15696M :)

I did some tests recently, it appears JFS is 20-60MB/s faster for 
sequential read/writes/re-writes but it does not have a defrag tool, 
defragfs but its not included in Debian and people say not to use it on 
Google/so I am not sure I want to go there.

Justin.