On 04.04.2015 19:08, Matthew Ahrens wrote: > Strided prefetch: mostly evil. > > I've rewritten the predictive prefetcher; new version only detects > forward sequential streams. Will propose for upstreaming soon. In the > mean time feel free to check out: > > https://github.com/delphix/delphix-os/commit/13cf8efe4b6b10930b478a15f9de92880bbdd412
Ah. Thank you. I haven't tried it yet, but I like some ideas there, while the rest can probably be justified by simplicity. I just slightly worry that with your patch single large read does not start prefetch. >From one side that may be counted as correct behavior (request was indeed only one and we have no idea whether there will be the second), but if the second request arrive -- cache has nothing for it at all, not even started. Generally I hope "soon" happen sooner then in another six months, otherwise we could start cutting out strides less aggressively, starting from my less invasive patch. ;) PS: FreeBSD code style does not recommend inline definition of variables, that you used several times in your patch. -- Alexander Motin _______________________________________________ developer mailing list [email protected] http://lists.open-zfs.org/mailman/listinfo/developer
