[ As a small note - if you are going to comment on the results table
from a previous message, please don't cut it from your response.
Context is important. I pasted the relevant part back in so i can
refer back to it in my response. ]
On Tue, Jan 25, 2011 at 08:39:00AM +0100, Emmanuel Florac wrote:
> Le Tue, 25 Jan 2011 10:03:14 +1100 vous écriviez:
> > > Version 1.96 ------Sequential Create------ --------Random Create--------
> > > A1 -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
> > > files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
> > > 16 104 0 +++++ +++ 115 0 89 0 +++++ +++ 111 0
> >
> > Only 16 files?
>
> IIRC this is 16 thousands of files. Though this is not enough, I
> generally use 80 to 160 for tests.
Yes, you're right, the bonnie++ man page states that it is in units
of 1024 files. Be nice if there was a "k" to signify that so people
who aren't intimately familiar with it's output format can see
exactly what was tested....
As it is, a create rate of 104 files/s (note the consistency of
units between 2 adjacent numbers!) indicates something else is
screwed, because my local test VM on RAID0 gets numbers like this:
Version 1.96 ------Sequential Create------ --------Random Create--------
test-4 -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
16 25507 90 +++++ +++ 30472 97 25281 93 +++++ +++ 29077 97
Latency 23864us 204us 21092us 18855us 82us 121us
IOWs, create rates of 25k/s and unlink of 30k/s and it is clearly
CPU bound.
Therein lies the difference: the original numbers have 0% CPU usage,
which indicates that the test is blocking. Something is causing the
reported test system to be blocked almost all the time.
/me looks closer.
Oh, despite $subject being "RAID0" the filesystems being tested are
on RAID5 and RAID6 with very small chunk sizes on slow SATA drives.
This is smelling like a case of barrier IOs on software raid on
cheap storage....
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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