> From: Jesper Dangaard Brouer <hawk@xxxxxxxxxx> > Date: Tue, 26 Nov 2024 18:12:27 +0100 > > > > > > > > > On 26/11/2024 18.02, Lorenzo Bianconi wrote: > >>> From: Daniel Xu <dxu@xxxxxxxxx> > >>> Date: Mon, 25 Nov 2024 16:56:49 -0600 > >>> > >>>> > >>>> > >>>> On Mon, Nov 25, 2024, at 9:12 AM, Alexander Lobakin wrote: > >>>>> From: Daniel Xu <dxu@xxxxxxxxx> > >>>>> Date: Fri, 22 Nov 2024 17:10:06 -0700 > >>>>> > >>>>>> Hi Olek, > >>>>>> > >>>>>> Here are the results. > >>>>>> > >>>>>> On Wed, Nov 13, 2024 at 03:39:13PM GMT, Daniel Xu wrote: > >>>>>>> > >>>>>>> > >>>>>>> On Tue, Nov 12, 2024, at 9:43 AM, Alexander Lobakin wrote: > >>>>> > >>>>> [...] > >>>>> > >>>>>> Baseline (again) > >>>>>> > >>>>>> Transactions Latency P50 (s) Latency P90 (s) Latency > >>>>>> P99 (s) Throughput (Mbit/s) > >>>>>> Run 1 3169917 0.00007295 0.00007871 > >>>>>> 0.00009343 Run 1 21749.43 > >>>>>> Run 2 3228290 0.00007103 0.00007679 > >>>>>> 0.00009215 Run 2 21897.17 > >>>>>> Run 3 3226746 0.00007231 0.00007871 > >>>>>> 0.00009087 Run 3 21906.82 > >>>>>> Run 4 3191258 0.00007231 0.00007743 > >>>>>> 0.00009087 Run 4 21155.15 > >>>>>> Run 5 3235653 0.00007231 0.00007743 > >>>>>> 0.00008703 Run 5 21397.06 > >>>>>> Average 3210372.8 0.000072182 0.000077814 > >>>>>> 0.00009087 Average 21621.126 > >>>>>> > >>>>>> cpumap v2 Olek > >>>>>> > >>>>>> Transactions Latency P50 (s) Latency P90 (s) Latency > >>>>>> P99 (s) Throughput (Mbit/s) > >>>>>> Run 1 3253651 0.00007167 0.00007807 > >>>>>> 0.00009343 Run 1 13497.57 > >>>>>> Run 2 3221492 0.00007231 0.00007743 > >>>>>> 0.00009087 Run 2 12115.53 > >>>>>> Run 3 3296453 0.00007039 0.00007807 > >>>>>> 0.00009087 Run 3 12323.38 > >>>>>> Run 4 3254460 0.00007167 0.00007807 > >>>>>> 0.00009087 Run 4 12901.88 > >>>>>> Run 5 3173327 0.00007295 0.00007871 > >>>>>> 0.00009215 Run 5 12593.22 > >>>>>> Average 3239876.6 0.000071798 0.00007807 > >>>>>> 0.000091638 Average 12686.316 > >>>>>> Delta 0.92% -0.53% 0.33% > >>>>>> 0.85% -41.32% > >>>>>> > >>>>>> > >>>>>> It's very interesting that we see -40% tput w/ the patches. I went > >>>>>> back > >>>>> > >>>>> Oh no, I messed up something =\ > >>>>> > >>>>> Could you please also test not the whole series, but patches 1-3 > >>>>> (up to > >>>>> "bpf:cpumap: switch to GRO...") and 1-4 (up to "bpf: cpumap: reuse skb > >>>>> array...")? Would be great to see whether this implementation works > >>>>> worse right from the start or I just broke something later on. > >>>> > >>>> Patches 1-3 reproduces the -40% tput numbers. > >>> > >>> Ok, thanks! Seems like using the hybrid approach (GRO, but on top of > >>> cpumap's kthreads instead of NAPI) really performs worse than switching > >>> cpumap to NAPI. > >>> > >>>> > >>>> With patches 1-4 the numbers get slightly worse (~1gbps lower) but > >>>> it was noisy. > >>> > >>> Interesting, I was sure patch 4 optimizes stuff... Maybe I'll give up > >>> on it. > >>> > >>>> > >>>> tcp_rr results were unaffected. > >>> > >>> @ Jakub, > >>> > >>> Looks like I can't just use GRO without Lorenzo's conversion to NAPI, at > >>> least for now =\ I took a look on the backlog NAPI and it could be used, > >>> although we'd need a pointer in the backlog to the corresponding cpumap > >>> + also some synchronization point to make sure backlog NAPI won't access > >>> already destroyed cpumap. > >>> > >>> Maybe Lorenzo could take a look... > >> > >> it seems to me the only difference would be we will use the shared > >> backlog_napi > >> kthreads instead of having a dedicated kthread for each cpumap entry > >> but we still > >> need the napi poll logic. I can look into it if you prefer the shared > >> kthread > >> approach. > > > > I don't like a shared kthread approach. For my use-case I want to give > > the "remote" CPU-map kthreads higher scheduling priority. (As it will be > > running a 2nd XDP BPF DDoS program protecting against overload by > > dropping packets). > > Oh, that is also valid. > Let's see what Jakub replies, for now I'm leaning towards posting > approach from this RFC with my bulk allocation from the NAPI cache. I guess it would be better to keep them separated to check what are the effects of each change (GRO for cpumap and bulk allocation). I guess you can post your changes on top of mine if we all agree the proposed approach is fine. What do you think? Regards, Lorenzo > > > > > Thus, I'm not a fan of using the shared backlog_napi. As I don't want > > to give backlog NAPI high priority, in my use-case. > > > >> @Jakub: what do you think? > > > > > > --Jesper > > Thanks, > Olek
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