On Tue 09-04-13 13:47:58, Andrew Morton wrote: > On Tue, 9 Apr 2013 17:42:49 +0200 Jan Kara <jack@xxxxxxx> wrote: > > > Currently, dio_send_cur_page() submits bio before current page and > > cached sdio->cur_page is added to the bio if sdio->boundary is set. This > > is actually wrong because sdio->boundary means the current buffer is the > > last one before metadata needs to be read. So we should rather submit > > the bio after the current page is added to it. > > > > Reported-by: Kazuya Mio <k-mio@xxxxxxxxxxxxx> > > Signed-off-by: Jan Kara <jack@xxxxxxx> > > --- > > fs/direct-io.c | 28 +++++++++++----------------- > > 1 files changed, 11 insertions(+), 17 deletions(-) > > > > Andrew, can you add this patch the previous direct IO boundary handling fix? > > What is the user-visible impact of these two patches? I've measured about 10% throughput improvement of direct IO reads on ext3 with SATA harddrive (from 90 MB/s to 100 MB/s) with these patches applied. With ramdisk, the improvement was about 3-fold (from 350 MB/s to 1.2 GB/s). For other filesystems (such as ext4), the improvements won't be as visible because the frequency of BH_Boundary flag being set is much smaller... Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- 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
