On Tue, 2010-06-08 at 14:49 -0400, Christoph Hellwig wrote: > Did this patch get merged somewhere? I dont think it ever did, about 1/2 of responses were for it and the other 1/2 against it. Larry > > On Thu, May 20, 2010 at 07:20:42AM -0400, Larry Woodman wrote: > > We've seen multiple performance regressions linked to the lower(20%) > > dirty_ratio. When performing enough IO to overwhelm the background > > flush daemons the percent of dirty pagecache memory quickly climbs > > to the new/lower dirty_ratio value of 20%. At that point all > > writing processes are forced to stop and write dirty pagecache pages > > back to disk. This causes performance regressions in several > > benchmarks as well as causing > > a noticeable overall sluggishness. We all know that the dirty_ratio is > > an integrity vs performance trade-off but the file system journaling > > will cover any devastating effects in the event of a system crash. > > > > Increasing the dirty_ratio to 40% will regain the performance loss seen > > in several benchmarks. Whats everyone think about this??? > > > > > > > > > > > > ------------------------------------------------------------------------ > > > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > > index ef27e73..645a462 100644 > > --- a/mm/page-writeback.c > > +++ b/mm/page-writeback.c > > @@ -78,7 +78,7 @@ int vm_highmem_is_dirtyable; > > /* > > * The generator of dirty data starts writeback at this percentage > > */ > > -int vm_dirty_ratio = 20; > > +int vm_dirty_ratio = 40; > > > > /* > > * vm_dirty_bytes starts at 0 (disabled) so that it is a function of > > > > -- > > To unsubscribe, send a message with 'unsubscribe linux-mm' in > > the body to majordomo@xxxxxxxxxx For more info on Linux MM, > > see: http://www.linux-mm.org/ . > > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> > ---end quoted text--- > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@xxxxxxxxxx For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>