Messages in this thread | | | From | Peter Oskolkov <> | Date | Fri, 21 May 2021 12:13:55 -0700 | Subject | Re: [RFC PATCH v0.1 0/9] UMCG early preview/RFC patchset |
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On Fri, May 21, 2021 at 11:44 AM Andrei Vagin <avagin@google.com> wrote: > > > > On Thu, May 20, 2021 at 11:36 AM Peter Oskolkov <posk@google.com> wrote: >> >> As indicated earlier in the FUTEX_SWAP patchset: >> >> https://lore.kernel.org/lkml/20200722234538.166697-1-posk@posk.io/ > > > Hi Peter, > > Do you have benchmark results? How fast is it compared with futex_swap and the google switchto?
Hi Andrei,
I did not run benchmarks on the same machine/kernel, but umcg_swap between "core" tasks (your use case for gVisor) should be somewhat faster than futex_swap, as there is no reading from the userspace and no futex hash lookup/dequeue ops; umcg_swap should be slower than switchto_switch because umcg_swap does go through ttwu+schedule, which switchto_switch bypasses.
I expect that if UMCG is merged in a form similar to what I posted, we will explore how to make UMCG context switches faster in later patches.
Thanks, Peter
> > Thanks, > Andrei
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