Re: [Ext2-devel] Re: [RFC][PATCH 0/2]Extend ext3 filesystem limit from 8TB to 16TB

[Laurent Vivier <Laurent.Vivier@bull.net>]

Le mar 18/04/2006 à 09:30, Arjan van de Ven a écrit :
> On Tue, 2006-04-18 at 09:14 +0200, Laurent Vivier wrote:
> > Le lun 17/04/2006 à 23:32, Ravikiran G Thirumalai a écrit :
> > > On Mon, Apr 17, 2006 at 11:09:36PM +0200, Arjan van de Ven wrote:
> > > > On Mon, 2006-04-17 at 14:07 -0700, Ravikiran G Thirumalai wrote:
> > > > > 
> > > > > 
> > > > > I ran the same tests on a 16 core EM64T box very similar to the one
> > > > > you ran
> > > > > dbench on :). Dbench results on ext3 varies quite a bit.  I couldn't
> > > > > get 
> > > > > to a statistically significant conclusion  For eg,
> > > > 
> > > > 
> > > > dbench is not a good performance benchmark. At all. Don't use it for
> > > > that ;)
> > > 
> > > Agreed. (I did not mean to use it in the first place :).  I was just trying 
> > > to verify the benchmark results posted earlier)
> > > 
> > > Thanks,
> > > Kiran
> > 
> > What is the good performance benchmark to know if we should use atomic_t
> > instead of percpu_counter ?
> 
> you probably want something like postal/postmark instead or so (although
> that's not ideal either), at least that's reproducable

I made tests on same system (x440) with postmark-1.51 :

pm> set numbers 100000
pm> set transactions 250000
pm> run

With atomic_t:

Time:
        3761 seconds total
        2414 seconds of transactions (103 per second)

Files:
        225064 created (59 per second)
                Creation alone: 100000 files (87 per second)
                Mixed with transactions: 125064 files (51 per second)
        124961 read (51 per second)
        124895 appended (51 per second)
        225064 deleted (59 per second)
                Deletion alone: 100128 files (503 per second)
                Mixed with transactions: 124936 files (51 per second)

Data:
        731.14 megabytes read (199.07 kilobytes per second)
        1359.02 megabytes written (370.02 kilobytes per second)

With percpu_counter:

Time:
        3787 seconds total
        2422 seconds of transactions (103 per second)

Files:
        225064 created (59 per second)
                Creation alone: 100000 files (85 per second)
                Mixed with transactions: 125064 files (51 per second)
        124961 read (51 per second)
        124895 appended (51 per second)
        225064 deleted (59 per second)
                Deletion alone: 100128 files (503 per second)
                Mixed with transactions: 124936 files (51 per second)

Data:
        731.14 megabytes read (197.70 kilobytes per second)
        1359.02 megabytes written (367.48 kilobytes per second)

-- 
Laurent Vivier
Bull, Architect of an Open World (TM)
http://www.bullopensource.org/ext4

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