Re: [BENCHMARK] 2.5.39 with contest 0.41

[Con Kolivas <conman@kolivas.net>]

Quoting Jens Axboe <axboe@suse.de>:

> On Sat, Sep 28 2002, Con Kolivas wrote:
> > > > io_load:
> > > > Kernel                  Time            CPU             Ratio
> > > > 2.4.19                  216.05          33%             3.19
> > > > 2.5.38                  887.76          8%              13.11*
> > > > 2.5.38-mm3              105.17          70%             1.55*
> > > > 2.5.39                  216.81          37%             3.20
> > > 
> > > -mm3 has fifo_batch=16.  2.5.39 has fifo_batch=32.
> 
> That's not the only difference, btw.
> 
> > > > mem_load:
> > > > Kernel                  Time            CPU             Ratio
> > > > 2.4.19                  105.40          70%             1.56
> > > > 2.5.38                  107.89          73%             1.59
> > > > 2.5.38-mm3              117.09          63%             1.73*
> > > > 2.5.39                  103.72          72%             1.53
> > > 
> > > 2.5's swapout is still fairly synchronously sucky.  So low-latency
> > > writeout could be advantageous there.  This difference is probably
> > > also the fifo_batch thing.  Or maybe statistical?
> > > 
> > > 
> > > I did some testing with your latest.  4xPIII, mem=512m, SCSI,
> > > tag depth = 0, 2.5.39-mm1 candidate:
> > > 
> > > fifo_batch=32:
> > > 
> > > 	noload          2:34.53         291%
> > > 	cpuload         2:36.20         286%
> > > 	memload         2:19.44         333%
> > > 	ioloadhalf      2:34.81         303%
> > > 	ioloadfull      3:15.47         238%
> > > 
> > > (err.  memload sped it up!)
> > > 
> > > fifo_batch=16:
> > > 
> > > 	noload          2:00.03         380%
> > > 	cpuload         2:27.62         304%
> > > 	memload         2:22.59         326%
> > > 	ioloadhalf      2:33.75         306%
> > > 	ioloadfull      2:59.18         259%
> > > 
> > > - Something went horridly wrong in the first `noload' test.
> > > - fifo_batch=16 is better than 32.
> > > - you see a 4x hit from io_load.  I see a 1.5x hit.
> 
> So far fifo_batch=16 looks pretty good. Doesn't quite make sense to me.
> Need to bench/test some more :-)

Andrew was using an older version of contest which may have been misrepresenting
things as there were serious limitations in the older versions.
I've directed him to the new version which has worked around (most) of the
limitations. SMP on the older version was particularly bad.

Con.