> -----Original Message----- > From: sheepdog-bounces at lists.wpkg.org > [mailto:sheepdog-bounces at lists.wpkg.org] On Behalf Of Christoph Hellwig > Sent: Tuesday, November 15, 2011 4:22 PM > To: Liu Yuan > Cc: Christoph Hellwig; sheepdog at lists.wpkg.org > Subject: Re: [Sheepdog] [PATCH] sheep: unify create_and_write logic for cow and > regular object > > On Tue, Nov 15, 2011 at 04:18:52PM +0800, Liu Yuan wrote: > > Umm, seems useless, I just squeeze it to the code path. any noticeable > > performance penalty? > > With the current O_SYNC I/O model it at least means an additional log > force, which on disks will be very noticeable. So unless you really > see a difference in I/O patterns don't do it. Just out of curiosity, won't fallocate() be a better hint to underlying file system which can then create a better on disk layout? With O_SYNC IO it forces allocation on each write... > > -- > sheepdog mailing list > sheepdog at lists.wpkg.org > http://lists.wpkg.org/mailman/listinfo/sheepdog |