Re: Performance 2.4.8 is worse than 2.4.x<8

On Sun, Aug 12, 2001 at 11:00:31AM -0300, Rik van Riel wrote:
> On Sun, 12 Aug 2001, Alan Cox wrote:
> 
> > > Here, disk write throughput seems to want some tweaking, and Bonnie
> > > doing it's rewrite test triggers a very large and persistant inactive
> > > shortage which shouldn't be there (imho).
> >
> > This is one of the reasons I kept the 2.4.7 vm. The 2.4.8 vm is better
> > than 2.4.8pre but not actually better than the older VM by feel or
> > measurement on my test boxes
> 
> There are some open-ended questions wrt. the use-once idea,
> its implementation and the way the thing has been integrated
> with the rest of the kernel.
> 
> Some suspect interactions and some things which just aren't
> clear yet don't make it seem the best idea to start integrating
> the use-once idea in mainli^W-ac yet...

Is it possible that this causes the slowdown I see when I benchmark
kernel compilations? Doing make -j2 bzImage modules on 2.4.7 gives:

        User time (seconds): 279.62
        System time (seconds): 22.19
        Percent of CPU this job got: 77%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 6:29.95
        ...
        Major (requiring I/O) page faults: 1085696
        Minor (reclaiming a frame) page faults: 1263226

With 2.4.8 (default bdflush settings):

        User time (seconds): 280.75
        System time (seconds): 21.46
        Percent of CPU this job got: 71%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 7:04.14
        ...
        Major (requiring I/O) page faults: 1085927
        Minor (reclaiming a frame) page faults: 1263289

With 2.4.8 (and 50/75 bdflush settings):

        User time (seconds): 282.20
        System time (seconds): 20.82
        Percent of CPU this job got: 71%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 7:03.27
        ...
        Major (requiring I/O) page faults: 1094004
        Minor (reclaiming a frame) page faults: 1265526

Since 2.4.8 should be better when running short of memory I tried
make -j bzImage modules also, with 2.4.7:

        User time (seconds): 294.16
        System time (seconds): 32.70
        Percent of CPU this job got: 32%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 16:40.38
        ...
        Major (requiring I/O) page faults: 1560301
        Minor (reclaiming a frame) page faults: 1601194

and with 2.4.8 (default bdflush)

        User time (seconds): 293.57
        System time (seconds): 50.55
        Percent of CPU this job got: 24%
        Elapsed (wall clock) time (h:mm:ss or m:ss): 23:35.30
        ...
        Major (requiring I/O) page faults: 1592833
        Minor (reclaiming a frame) page faults: 1556612

System is an Athlon-1.2GHz with 256MB DDR-Ram.

If you want further compilation benchmarks just let me know.

Regards,

   Jogi

-- 

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