On Wed, Jun 06, 2012 at 08:14:08AM -0400, Vivek Goyal wrote: [..] > I think it is happening because sync_file_range() will send all > the writes as SYNC and it will compete with firefox IO. On the other > hand, flusher's IO will show up as ASYNC and CFQ will be penalize it > heavily and firefox's IO will be prioritized. And this effect should > just get worse as more processes do sync_file_range(). Ok, this time I tried the same test again but with 4 processes doing writes in parallel on 4 different files. And with sync_file_range() things turned ugly. Interactivity was very poor. firefox launch test took around 1m:45s with sync_file range() while it took only about 35seconds with regular flusher threads. So sending writeback IO synchronously wreaks havoc. Thanks Vivek -- 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
