Date: Tue, 9 Jan 2007 13:32:07 -0300 From: "Victor Loureiro Lima" <victorloureirolima@gmail.com> To: Fluffles <etc@fluffles.net> Cc: freebsd-fs@freebsd.org, Ivan Voras <ivoras@fer.hr>, freebsd-geom@freebsd.org Subject: Re: Capturing I/O traces Message-ID: <ac00e00a0701090832o60b9a0eev67b63cc00ff9688a@mail.gmail.com> In-Reply-To: <45A396C5.2000908@fluffles.net> References: <45A38D38.3020407@fluffles.net> <eo049r$th4$1@sea.gmane.org> <45A396C5.2000908@fluffles.net>
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Maybe you could take a look at iostat(8), seems to be able to help you somehow!!! ;) att, victor loureiro lima 2007/1/9, Fluffles <etc@fluffles.net>: > Ivan Voras wrote: > > Fluffles wrote: > > > > > >> One thought that comes to mind is the gnop geom class; with verbose mode > >> this provides a text log of all the I/O accesses. But it does not > >> provide the exact time/concurrency etc, only the offset, length, I/O > >> > > > > What do you mean by "time" and "concurrency"? You do realize that > > requests are serialized on the low level? > > > > Sure but simply capturing the serial order of requests might not be > sufficient. For example: the application might 'wait' for one request to > be finished because it needs that data in order to do another I/O > request. I guess this is the hard part. If i would just execute the I/O > in a serial way things like accesstime or 'latency' are less important > because the overall throughput counts; while this may not be true for > real applications but they might wait on one request before they can > move on; thus a lower latency might be more important than a higher > throughput. > > I guess it's not easy to really make something like this be reliable and > realistic, but i'd like to come as close as possible. For example, the > website StorageReview also uses traces to benchmark specific uses, two > links: > > http://www.storagereview.com/articles/200611/ST3750640NS_3.html > http://www.storagereview.com/articles/200510/Testbed4_4.html > > I'd like to use traces of applications on FreeBSD (or GNU/Linux) to > benchmark KDE startup, MySQL, Apache and other applications. So i can > have benchmark suites like "desktop", "webserver" and "database". That > would be very neat. > > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" >
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