On Wed, Sep 17, 2025 at 04:59:41PM -0700, Suren Baghdasaryan wrote: > On Wed, Sep 17, 2025 at 9:14 AM Suren Baghdasaryan <sur...@google.com> wrote: > > > > On Tue, Sep 16, 2025 at 10:19 PM Uladzislau Rezki <ure...@gmail.com> wrote: > > > > > > On Tue, Sep 16, 2025 at 10:09:18AM -0700, Suren Baghdasaryan wrote: > > > > On Mon, Sep 15, 2025 at 8:22 AM Vlastimil Babka <vba...@suse.cz> wrote: > > > > > > > > > > On 9/15/25 14:13, Paul E. McKenney wrote: > > > > > > On Mon, Sep 15, 2025 at 09:51:25AM +0200, Jan Engelhardt wrote: > > > > > >> > > > > > >> On Saturday 2025-09-13 02:09, Sudarsan Mahendran wrote: > > > > > >> > > > > > > >> >Summary of the results: > > > > > > > > > > In any case, thanks a lot for the results! > > > > > > > > > > >> >- Significant change (meaning >10% difference > > > > > >> > between base and experiment) on will-it-scale > > > > > >> > tests in AMD. > > > > > >> > > > > > > >> >Summary of AMD will-it-scale test changes: > > > > > >> > > > > > > >> >Number of runs : 15 > > > > > >> >Direction : + is good > > > > > >> > > > > > >> If STDDEV grows more than mean, there is more jitter, > > > > > >> which is not "good". > > > > > > > > > > > > This is true. On the other hand, the mean grew way more in absolute > > > > > > terms than did STDDEV. So might this be a reasonable tradeoff? > > > > > > > > > > Also I'd point out that MIN of TEST is better than MAX of BASE, which > > > > > means > > > > > there's always an improvement for this config. So jitter here means > > > > > it's > > > > > changing between better and more better :) and not between worse and > > > > > (more) > > > > > better. > > > > > > > > > > The annoying part of course is that for other configs it's > > > > > consistently the > > > > > opposite. > > > > > > > > Hi Vlastimil, > > > > I ran my mmap stress test that runs 20000 cycles of mmapping 50 VMAs, > > > > faulting them in then unmapping and timing only mmap and munmap calls. > > > > This is not a realistic scenario but works well for A/B comparison. > > > > > > > > The numbers are below with sheaves showing a clear improvement: > > > > > > > > Baseline > > > > avg stdev > > > > mmap 2.621073 0.2525161631 > > > > munmap 2.292965 0.008831973052 > > > > total 4.914038 0.2572620923 > > > > > > > > Sheaves > > > > avg stdev avg_diff stdev_diff > > > > mmap 1.561220667 0.07748897037 -40.44% -69.31% > > > > munmap 2.042071 0.03603083448 -10.94% 307.96% > > > > total 3.603291667 0.113209047 -26.67% -55.99% > > > > > > > Could you run your test with dropping below patch? > > > > Sure, will try later today and report. > > Sheaves with [04/23] patch reverted: > > avg avg_diff > mmap 2.143948 -18.20% > munmap 2.343707 2.21% > total 4.487655 -8.68% > With offloading over sheaves the mmap/munmap is faster, i assume it is because of same objects are reused from the sheaves after reclaim. Whereas we, kvfree_rcu() just free them. Thank you for your results.
-- Uladzislau Rezki
