On Sat, 28 Apr 2007 10:04:08 +0200 Peter Zijlstra <[EMAIL PROTECTED]> wrote:
> > > > The other thing is that we can batch up pagecache page insertions for bulk > > writes as well (that is. write(2) with buffer size > page size). I should > > have a patch somewhere for that as well if anyone interested. > > Together with the optimistic locking from my concurrent pagecache that > should bring most of the gains: > > sequential insert of 8388608 items: > > CONFIG_RADIX_TREE_CONCURRENT=n > > [ffff81007d7f60c0] insert 0 done in 15286 ms > > CONFIG_RADIX_TREE_OPTIMISTIC=y > > [ffff81006b36e040] insert 0 done in 3443 ms > > only 4.4 times faster, and more scalable, since we don't bounce the > upper level locks around. I'm not sure what we're looking at here. radix-tree changes? Locking changes? Both? If we have a whole pile of pages to insert then there are obvious gains from not taking the lock once per page (gang insert). But I expect there will also be gains from not walking down the radix tree once per page too: walk all the way down and populate all the way to the end of the node. The implementation could get a bit tricky, handling pages which a racer instantiated when we dropped the lock, and suitably adjusting ->index. Not rocket science though. The depth of the radix tree matters (ie, the file size). 'twould be useful to always describe the tree's size when publishing microbenchmark results like this. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
