On Wed, Jul 08, 2020 at 04:57:56PM +0200, Holger Hoffstätte wrote: > On 2020-07-08 16:04, David Sterba wrote: > > On Wed, Jul 08, 2020 at 10:19:22AM +0800, Robbie Ko wrote: > >> David Sterba 於 2020/7/8 上午3:25 寫道: > >> I don't know why we don't make the change to readahead, because the current > >> readahead is limited to the logical address in 64k is very unreasonable, > >> and there is a good chance that the logical address of the next leaf > >> node will > >> not appear in 64k, so the existing readahead is almost useless. > > > > I see and it seems that the assumption about layout and chances > > succesfuly read blocks ahead is not valid. The logic of readahead could > > be improved but that would need more performance evaluation. > > FWIW I gave this a try and see the following numbers, averaged over multiple > mount/unmount cycles on spinning rust: > > without patch : ~2.7s > with patch : ~4.5s > > ..ahem.. Hard to argue against numbers, thanks for posting that.
