On Mon, Aug 19, 2013 at 09:24:14PM +0200, Heinz Diehl wrote: > On 19.08.2013, Mihai T. Lazarescu wrote: > > > It appears that CFQ can sense and adapt to SSD and has little > > if any loss to other I/O schedulers: > > > http://www.velobit.com/storage-performance-blog/bid/126135/Effects-Of-Linux-IO-Scheduler-On-SSD-Performance > > They only tested bandwidth, not latency. On my systems, > deadline outperforms cfq, both wrt bandwidth *and* latency, > both felt and measured. Latency is especially sensible when > there's a lot of disk I/O. You can do some testing using > Ted Tso's fsync-tester: > > https://oss.oracle.com/~mason/fsync-tester.c Thanks for the pointer. I add to the mix my test results for F19 with kernel 3.10.7 on an ASUS UX31E with its factory 256GB SSD-only mass storage. CFQ scheduler run1: write time: 0.0007s fsync time: 0.9397s write time: 0.0004s fsync time: 5.6349s write time: 0.0004s fsync time: 1.1586s write time: 0.0004s fsync time: 14.4159s write time: 0.0004s fsync time: 12.7619s write time: 0.0004s fsync time: 13.5689s CFQ scheduler run2: write time: 0.0010s fsync time: 0.9970s write time: 0.0004s fsync time: 5.7953s write time: 0.0004s fsync time: 0.9726s write time: 0.0004s fsync time: 14.9300s write time: 0.0005s fsync time: 0.7052s write time: 0.0004s fsync time: 8.3616s write time: 0.0004s fsync time: 2.1200s write time: 0.0004s fsync time: 4.5161s Deadline scheduler run1: write time: 0.0007s fsync time: 1.6141s write time: 0.0005s fsync time: 11.2728s write time: 0.0005s fsync time: 18.5445s write time: 8.0272s fsync time: 23.0132s Deadline scheduler run2: write time: 0.0137s fsync time: 0.9517s write time: 0.0005s fsync time: 11.5287s write time: 0.0005s fsync time: 17.4877s write time: 0.0005s fsync time: 12.9626s write time: 0.0004s fsync time: 56.6898s Noop scheduler run1: write time: 0.0062s fsync time: 1.2807s write time: 0.0005s fsync time: 11.4450s write time: 0.0005s fsync time: 18.3745s write time: 7.6150s fsync time: 25.1109s Noop scheduler run2: write time: 0.0099s fsync time: 1.3952s write time: 0.0004s fsync time: 11.3167s write time: 0.0004s fsync time: 19.0572s write time: 7.4895s fsync time: 25.1773s Mihai -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines Have a question? Ask away: http://ask.fedoraproject.org
