From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4636DC83F12 for ; Tue, 29 Aug 2023 10:07:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232769AbjH2KG6 (ORCPT ); Tue, 29 Aug 2023 06:06:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46728 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231263AbjH2KG0 (ORCPT ); Tue, 29 Aug 2023 06:06:26 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B04CBEC for ; Tue, 29 Aug 2023 03:06:15 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 508B063FCA for ; Tue, 29 Aug 2023 10:06:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E359C433C7; Tue, 29 Aug 2023 10:06:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1693303574; bh=bV4kk+JXZFzlioca80GXNZZ/6bCd7OPUpA3PfumE5e8=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=c5vNhYVZt6btB9chI8TRb1vy39btLX9U3biaX/KLaGSq4M7Q7uTg2hRN/nubKAUvM iYVzjU5hGHPtB/H07odIOuo+EKKaOqDbK7noA7F3YgvXmW/ZREapqYVt/VOTvRRJ/C JjCg3beb9+aZkQigvLWHlpDwnCT35CRLqRT11T//YTdx6agsJrlvjQL+VqR5g1LFBG KgXyR1WvvhbhZ7iyWlVIZuAxL4SPZcXLeyTOlmL4dM3PJ9lfFGyYUOrdqC/2LgEZKG uDqdEToKs6TNde3Ov2H3r1vt0qJaJfBDiCKG+i863vlXwVIHx04uvA+UEdQ2G8qaxr mZOVECqKbDQ6g== From: =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= To: Puranjay Mohan , paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, pulehui@huawei.com, conor.dooley@microchip.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, kpsingh@kernel.org, bpf@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Cc: puranjay12@gmail.com Subject: Re: [PATCH bpf-next v3 0/3] bpf, riscv: use BPF prog pack allocator in BPF JIT In-Reply-To: <20230828165958.1714079-1-puranjay12@gmail.com> References: <20230828165958.1714079-1-puranjay12@gmail.com> Date: Tue, 29 Aug 2023 12:06:11 +0200 Message-ID: <87edjmb1t8.fsf@all.your.base.are.belong.to.us> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Puranjay Mohan writes: > Changes in v2 -> v3: > 1. Fix maximum width of code in patches from 80 to 100. [All patches] > 2. Add checks for ctx->ro_insns =3D=3D NULL. [Patch 3] > 3. Fix check for edge condition where amount of text to set > 2 * pagesize > [Patch 1 and 2] > 4. Add reviewed-by in patches. > 5. Adding results of selftest here: > Using the command: ./test_progs on qemu > Without the series: Summary: 336/3162 PASSED, 56 SKIPPED, 90 FAILED > With this series: Summary: 336/3162 PASSED, 56 SKIPPED, 90 FAILED > > Changes in v1 -> v2: > 1. Implement a new function patch_text_set_nosync() to be used in bpf_arc= h_text_invalidate(). > The implementation in v1 called patch_text_nosync() in a loop and it w= as bad as it would > call flush_icache_range() for every word making it really slow. This w= as found by running > the test_tag selftest which would take forever to complete. > > Here is some data to prove the V2 fixes the problem: > > Without this series: > root@rv-selftester:~/src/kselftest/bpf# time ./test_tag > test_tag: OK (40945 tests) > > real 7m47.562s > user 0m24.145s > sys 6m37.064s > > With this series applied: > root@rv-selftester:~/src/selftest/bpf# time ./test_tag > test_tag: OK (40945 tests) > > real 7m29.472s > user 0m25.865s > sys 6m18.401s > > BPF programs currently consume a page each on RISCV. For systems with man= y BPF > programs, this adds significant pressure to instruction TLB. High iTLB pr= essure > usually causes slow down for the whole system. > > Song Liu introduced the BPF prog pack allocator[1] to mitigate the above = issue. > It packs multiple BPF programs into a single huge page. It is currently o= nly > enabled for the x86_64 BPF JIT. > > I enabled this allocator on the ARM64 BPF JIT[2]. It is being reviewed no= w. > > This patch series enables the BPF prog pack allocator for the RISCV BPF J= IT. > This series needs a patch[3] from the ARM64 series to work. > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D > Performance Analysis of prog pack allocator on RISCV64 > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D > > Test setup: > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > Host machine: Debian GNU/Linux 11 (bullseye) > Qemu Version: QEMU emulator version 8.0.3 (Debian 1:8.0.3+dfsg-1) > u-boot-qemu Version: 2023.07+dfsg-1 > opensbi Version: 1.3-1 > > To test the performance of the BPF prog pack allocator on RV, a stresser > tool[4] linked below was built. This tool loads 8 BPF programs on the sys= tem and > triggers 5 of them in an infinite loop by doing system calls. > > The runner script starts 20 instances of the above which loads 8*20=3D160= BPF > programs on the system, 5*20=3D100 of which are being constantly triggere= d. > The script is passed a command which would be run in the above environmen= t. > > The script was run with following perf command: > ./run.sh "perf stat -a \ > -e iTLB-load-misses \ > -e dTLB-load-misses \ > -e dTLB-store-misses \ > -e instructions \ > --timeout 60000" > > The output of the above command is discussed below before and after enabl= ing the > BPF prog pack allocator. > > The tests were run on qemu-system-riscv64 with 8 cpus, 16G memory. The ro= otfs > was created using Bjorn's riscv-cross-builder[5] docker container linked = below. > > Results > =3D=3D=3D=3D=3D=3D=3D > > Before enabling prog pack allocator: > ------------------------------------ > > Performance counter stats for 'system wide': > > 4939048 iTLB-load-misses > 5468689 dTLB-load-misses > 465234 dTLB-store-misses > 1441082097998 instructions > > 60.045791200 seconds time elapsed > > After enabling prog pack allocator: > ----------------------------------- > > Performance counter stats for 'system wide': > > 3430035 iTLB-load-misses > 5008745 dTLB-load-misses > 409944 dTLB-store-misses > 1441535637988 instructions > > 60.046296600 seconds time elapsed > > Improvements in metrics > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > It was expected that the iTLB-load-misses would decrease as now a single = huge > page is used to keep all the BPF programs compared to a single page for e= ach > program earlier. > > -------------------------------------------- > The improvement in iTLB-load-misses: -30.5 % > -------------------------------------------- > > I repeated this expriment more than 100 times in different setups and the > improvement was always greater than 30%. > > This patch series is boot tested on the Starfive VisionFive 2 board[6]. > The performance analysis was not done on the board because it doesn't > expose iTLB-load-misses, etc. The stresser program was run on the board t= o test > the loading and unloading of BPF programs > > [1] https://lore.kernel.org/bpf/20220204185742.271030-1-song@kernel.org/ > [2] https://lore.kernel.org/all/20230626085811.3192402-1-puranjay12@gmail= .com/ > [3] https://lore.kernel.org/all/20230626085811.3192402-2-puranjay12@gmail= .com/ > [4] https://github.com/puranjaymohan/BPF-Allocator-Bench > [5] https://github.com/bjoto/riscv-cross-builder > [6] https://www.starfivetech.com/en/site/boards > > Puranjay Mohan (3): > riscv: extend patch_text_nosync() for multiple pages > riscv: implement a memset like function for text > bpf, riscv: use prog pack allocator in the BPF JIT Thank you! For the series: Acked-by: Bj=C3=B6rn T=C3=B6pel Tested-by: Bj=C3=B6rn T=C3=B6pel @Alexei @Daniel This series depends on a core BPF patch from the Arm series [3]. @Palmer LMK if you have any concerns taking the RISC-V text patching stuff via the BPF tree. Bj=C3=B6rn