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Greg KH wrote: >On Tue, Mar 14, 2006 at 03:49:16PM -0500, Shailabh Nagar wrote: > >>>Greg KH wrote:>>>> >>>>>On Mon, Mar 13, 2006 at 07:40:34PM -0500, Shailabh Nagar wrote: >>>>>>>>> >>>>>>>This is the next iteration of the delay accounting patches >>>>last posted at>>>>http://www.ussg.iu.edu/hypermail/linux/kernel/0602.3/0893.html>>>> >>>>>>>> >>>>>>>Do you have any benchmark numbers with this patch applied and with it >>>not applied? >>>>>> >>>>>None yet. Wanted to iron out the collection/utility aspects a bit before >>going into>>the performance impact.>>>>But this seems as good a time as any to collect some stats >>using the usual suspects lmbench, kernbench, hackbench etc. >>>> >>>>>Last I heard it was a measurable decrease for some>>>"important" benchmark results... >>> >>> >>> >>>>>Might have been from an older iteration where schedstats was fully enabled. >>But no point speculating....will run with this set of patches and see >>what shakes out.>>>>One point about the overhead is that it depends on the frequency with >>which data is>>collected. So a proper test would probably be a comparison of a >>non-patched kernel>>with>>a) patches applied but delay accounting not turned on at boot i.e. cost >>of the checks>>b) delay accounting turned on but not being read>> >>>>This is probably the most important one, as that is what distros will be >looking at. They will have to enable the option, but will not "turn it >on".> > I guess you meant a), not b) but yes, will run them in all these modes. > >>>c) delay accounting turned on and data read for all tasks at some >>"reasonable" rate >> >>Will that be good ? Other suggestions welcome. >> >>>>How about real benchmarks? The ones that the big companies look at? I >know you have access to them :)> > Hmm...though you also know, from working for some "big company", that it might take a while to get such data since one has to stand in queue :-) I'll try, and also explore the OSDL STP's DBT tests. Thanks, Shailabh >thanks,>>greg k-h> > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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