On 15/01/2020 10:39, Roger Pau Monné wrote: > On Tue, Jan 14, 2020 at 08:35:45PM +0000, Andrew Cooper wrote: >> Xen inherited its list infrastructure from Linux. One area where has fallen >> behind is that of prefetching, which as it turns out is a performance penalty >> in most cases. >> >> Prefetch of NULL on x86 is now widely measured to have glacial performance >> properties, and will unconditionally hit on every hlist use due to the >> termination condition. >> >> Cross-port the following Linux patches: >> >> 75d65a425c (2011) "hlist: remove software prefetching in hlist iterators" >> e66eed651f (2011) "list: remove prefetching from regular list iterators" >> c0d15cc7ee (2013) "linked-list: Remove __list_for_each" >> >> to Xen, which results in the following net diffstat on x86: >> >> add/remove: 0/1 grow/shrink: 27/83 up/down: 576/-1648 (-1072) >> >> (The code additions comes from a few now-inlined functions, and slightly >> different basic block padding.) >> >> No functional change. >> >> Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com> > Reviewed-by: Roger Pau Monné <roger....@citrix.com> > > Has this gone through some XenRT performance testing to assert there > are not regressions performance wise?
No. The Linux measurements are still valid observations. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
