On Wed, May 20, 2009 at 09:43:18AM +0800, Hisashi Hifumi wrote: > > At 10:07 09/05/20, KOSAKI Motohiro wrote: > >(cc to Wu and linux-mm) > > > >> Hi. > >> > >> I wrote a patch that adds blk_run_backing_dev on page_cache_async_readahead > >> so readahead I/O is unpluged to improve throughput. > >> > >> Following is the test result with dd. > >> > >> #dd if=testdir/testfile of=/dev/null bs=16384 > >> > >> -2.6.30-rc6 > >> 1048576+0 records in > >> 1048576+0 records out > >> 17179869184 bytes (17 GB) copied, 224.182 seconds, 76.6 MB/s > >> > >> -2.6.30-rc6-patched > >> 1048576+0 records in > >> 1048576+0 records out > >> 17179869184 bytes (17 GB) copied, 206.465 seconds, 83.2 MB/s > >> > >> Sequential read performance on a big file was improved. > >> Please merge my patch. > > > >I guess the improvement depend on readahead window size. > >Have you mesure random access workload? > > I tried with iozone. But there was no difference. It does not impact random IO because the patch only modified the *async* readahead path, and random IO is obviously *sync* ones. -- 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
