Hi Vivek, From: Ryo Tsuruta <ryov@xxxxxxxxxxxxx> Subject: [PATCH 1/1] dm-ioband: I/O bandwidth controller Date: Tue, 19 May 2009 17:39:28 +0900 (JST) > Hi Alasdair and all, > > This is the dm-ioband version 1.11.0 release. This patch can be > applied cleanly to current agk's tree. Alasdair, please give some > comments and suggestions. > > Changes from the previous release: > - Classify IOs in sync/async instead of read/write since the IO > request allocation/congestion logic were changed to be sync/async > based. > - IOs belong to the real-time class are dispatched in preference to > other IOs, regardless of the assigned bandwidth. I ran your script from the following URL to see IOs belong to the real-time class take precedence. http://linux.derkeiler.com/Mailing-Lists/Kernel/2009-04/msg08355.html Script ====== # /dev/mapper/ioband1 is mounted on /mnt1 rm /mnt1/aggressivewriter sync echo 3 > /proc/sys/vm/drop_caches # launch an hostile writer ionice -c2 -n7 dd if=/dev/zero of=/mnt1/aggressivewriter \ bs=4K count=524288 conv=fdatasync & # Reader ionice -c1 -n0 dd if=/mnt1/testzerofile1 of=/dev/null & wait $! echo "reader finished" old dm-ioband ============= First run 2147483648 bytes (2.1 GB) copied, 100.343 seconds, 21.4 MB/s (Reader) reader finished 2147483648 bytes (2.1 GB) copied, 101.107 seconds, 21.2 MB/s (Writer) new dm-ioband v1.11.0 ===================== First run 2147483648 bytes (2.1 GB) copied, 35.0623 seconds, 61.2 MB/s (Reader) reader finished 2147483648 bytes (2.1 GB) copied, 87.6979 seconds, 24.5 MB/s (Writer) The RT reader took precedence over the aggressive writer, regardless of assigned bandwidth. However, I think that some sort of limitation for RT IOs is needed. What do you think? Thanks, Ryo Tsuruta -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
