On Thu, Jun 9, 2011 at 2:06 PM, Benny Halevy <bhalevy@xxxxxxxxxxx> wrote: > On 2011-06-08 03:15, Peng Tao wrote: >> On 6/8/11, Jim Rees <rees@xxxxxxxxx> wrote: >>> Benny Halevy wrote: >>> >>> Â NAK. >>> Â This affects all layout types. ÂIn particular it is undesired >>> Â for write layouts that extend the file with the objects layout. >>> Â The server can extend the layout segments range >>> Â over what the client requested so why would the client >>> Â ask for artificially large layouts? >>> >>> This has actually been the subject of some debate over Thursday night >>> beers. ÂThe problem we're trying to solve is that the client is spending 98% >>> of its time in layoutget. ÂThis patch gives us something like a 10x >>> speedup. ÂBut many of us think it's not the right fix. ÂI suggest we discuss >>> next week. >>> > > Sure. > >>> But note that this patch doesn't change anything unless you set the sysctl. >> there is a default value of 2M. maybe we can set it to page size by >> default so other layout are not affected and block layout can let >> users set it by hand if they care about performance. does this make >> sense? > > If doing it at all why use a sysctl rather than a mount option? The purpose of using a sysctl is to give client the ability to change it on the fly. In theory, layout prefetching can benefit all layout types. So the patch tries to solve it in the pnfs generic layer. > Or maybe coding the logic for prefetching the layout iff sequential > access is detected is the right thing to do. Yeah, automatic decision should be a better way. > > Benny > >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>> More majordomo info at Âhttp://vger.kernel.org/majordomo-info.html >>> >> >> > -- Thanks, -Bergwolf -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
