We're using CFQ. CONFIG_DEFAULT_IOSCHED="cfq" ... CONFIG_IOSCHED_CFQ=y CONFIG_IOSCHED_DEADLINE=y CONFIG_IOSCHED_NOOP=y On Thu, Jun 25, 2015 at 5:58 PM, Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx> wrote: > Hello, > > On (06/25/15 11:24), Luigi Semenzato wrote: >> I looked at this some more and I am not sure that there is any bug, or >> other possible tuning. >> >> While the random-write process runs, iostat -x -k 1 reports these numbers: >> >> average queue size: around 300 >> average write wait: typically 200 to 400 ms, but can be over 1000 ms >> average read wait: typically 50 to 100 ms >> >> (more info at crbug.com/414709) >> >> The read latency may be enough to explain the jank. In addition, the >> browser can do fsyncs, and I think that those will block for a long >> time. >> >> Ionice doesn't seem to make a difference. I suspect that once the >> blocks are in the output queue, it's first-come/first-serve. Is this >> correct or am I confused? >> >> We can fix this on the application side but only partially. The OS >> version updater can use O_SYNC. The problem is that his can happen in >> a number of situations, such as when simply downloading a large file, >> and in other code we don't control. >> > > do you use CONFIG_IOSCHED_DEADLINE or CONFIG_IOSCHED_CFQ? > > -ss -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>