On Mon, Jul 13, 2009 at 08:47:31PM +0800, Ronald Moesbergen wrote: > 2009/7/13 Wu Fengguang <fengguang.wu@xxxxxxxxx>: > > On Mon, Jul 13, 2009 at 08:12:14PM +0800, Ronald Moesbergen wrote: > >> 2009/7/10 Vladislav Bolkhovitin <vst@xxxxxxxx>: > >> > > >> > Vladislav Bolkhovitin, on 07/10/2009 12:43 PM wrote: > >> >> > >> >> Ronald Moesbergen, on 07/10/2009 10:32 AM wrote: > >> >>>> > >> >>>> I've also long ago noticed that reading data from block devices is > >> >>>> slower > >> >>>> than from files from mounted on those block devices file systems. Can > >> >>>> anybody explain it? > >> >>>> > >> >>>> Looks like this is strangeness #2 which we uncovered in our tests (the > >> >>>> first > >> >>>> one was earlier in this thread why the context RA doesn't work with > >> >>>> cooperative I/O threads as good as it should). > >> >>>> > >> >>>> Can you rerun the same 11 tests over a file on the file system, please? > >> >>> > >> >>> I'll see what I can do. Just te be sure: you want me to run > >> >>> blockdev-perftest on a file on the OCFS2 filesystem which is mounted > >> >>> on the client over iScsi, right? > >> >> > >> >> Yes, please. > >> > > >> > Forgot to mention that you should also configure your backend storage as a > >> > big file on a file system (preferably, XFS) too, not as direct device, like > >> > /dev/vg/db-master. > >> > >> Ok, here are the results: > > > > Ronald, thanks for the numbers! > > You're welcome. > > >> client kernel: 2.6.26-15lenny3 (debian) > >> server kernel: 2.6.29.5 with readahead patch > > > > Do you mean the context readahead patch? > > No, I meant the blk_run_backing_dev patch. The patchnames are > confusing, I'll be sure to clarify them from now on. That's OK. I did see previous benchmarks were not helped by context readahead noticeably on CFQ, hehe. Thanks, Fengguang -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
