From patchwork Mon Oct 21 12:21:07 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Puranjay Mohan X-Patchwork-Id: 13844010 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 93C371E9089; Mon, 21 Oct 2024 12:21:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729513309; cv=none; b=jmAK7SwkXGdIBc8XiwaPh1p9+t8xK1vby0bklFygH4l1GDTz9M2ilkDgl18eBtQQOe+0zKHw7gh/sapci34IlQ2nwNZSSo+9TLg1KST2SoSNn110sO6ulw2SDJXEXxWoGyzTFyhA7N82cEdm7yQZaaCedYuBmy3lKQwgejMEAcE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729513309; c=relaxed/simple; bh=B+VLaGzReOrXQUVLIvCM19MOqgqdL54YeTdVPYr1sHM=; h=From:To:Subject:Date:Message-Id:MIME-Version:Content-Type; b=Omxdt+S8XfM9a4ldGG4dDXWBczBrudKc6wMIZe6qmqITUHUy+TKbV0jp1zB+DAE7YdzHWfHgUF+QVXxu1CNpbQ7JW2AngowkqA2AV8uNuBBz5W5JbW9N7qcsPYYmBJR34+8na2p6hW3P54P6Ds6QhT+C3iQRRZoBP0w+/3ixrBk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tVl0pom3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="tVl0pom3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E698DC4CEE7; Mon, 21 Oct 2024 12:21:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729513309; bh=B+VLaGzReOrXQUVLIvCM19MOqgqdL54YeTdVPYr1sHM=; h=From:To:Subject:Date:From; b=tVl0pom3rlQe9aM/hjZ2mYpEz9YDCN23RGwaN9xZrSTEM2rUBrH15X28wEw3PBlIm qRuLpl0iHy18hzGeMt2rGGufKslkKulrKhttEx1kmWCanhwkkTkUTeKzxMmxVGIkva hlGnv6PW2rwYgMsQsXxnVVn5a8k+S5yXKvZ8S61dHW6V8Oh3a4jKGJnC9MqDoPQ/u9 6Zj6PuEW+UMpWRIYGbjIcrX0t3aqzSVaNpAJWrulIgJTPsj1ShjMQBCeOLvDNoMP8u C4sR0vQ0mQVbUvB2yT27z3AGXxlnJvrQ71jlY6EQMVKKpryk7Nst7E/i9TA0rYC3oa 18svTXbxvvipw== From: Puranjay Mohan To: Albert Ou , Alexei Starovoitov , Andrew Morton , Andrii Nakryiko , bpf@vger.kernel.org, Daniel Borkmann , "David S. Miller" , Eduard Zingerman , Eric Dumazet , Hao Luo , Helge Deller , Jakub Kicinski , "James E.J. Bottomley" , Jiri Olsa , John Fastabend , KP Singh , linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org, linux-riscv@lists.infradead.org, Martin KaFai Lau , Mykola Lysenko , netdev@vger.kernel.org, Palmer Dabbelt , Paolo Abeni , Paul Walmsley , Puranjay Mohan , Puranjay Mohan , Shuah Khan , Song Liu , Stanislav Fomichev , Yonghong Song Subject: [PATCH bpf-next 0/5] Optimize bpf_csum_diff() and homogenize for all archs Date: Mon, 21 Oct 2024 12:21:07 +0000 Message-Id: <20241021122112.101513-1-puranjay@kernel.org> X-Mailer: git-send-email 2.40.1 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net The bpf_csum_diff() helper currently returns different values on different architectures because it calls csum_partial() that is either implemented by the architecture like x86_64, arm, etc or uses the generic implementation in lib/checksum.c like arm64, riscv, etc. The implementation in lib/checksum.c returns the folded result that is 16-bit long, but the architecture specific implementation can return an unfolded value that is larger than 16-bits. The helper uses a per-cpu scratchpad buffer for copying the data and then computing the csum on this buffer. This can be optimised by utilising some mathematical properties of csum. The patch 1 in this series does preparatory work for homogenizing the helper. patch 2 does the changes to the helper itself. The performance gain can be seen in the tables below that are generated using the benchmark built in patch 4: x86-64: +-------------+------------------+------------------+-------------+ | Buffer Size | Before | After | Improvement | +-------------+------------------+------------------+-------------+ | 4 | 2.296 ± 0.066M/s | 3.415 ± 0.001M/s | 48.73 % | | 8 | 2.320 ± 0.003M/s | 3.409 ± 0.003M/s | 46.93 % | | 16 | 2.315 ± 0.001M/s | 3.414 ± 0.003M/s | 47.47 % | | 20 | 2.318 ± 0.001M/s | 3.416 ± 0.001M/s | 47.36 % | | 32 | 2.308 ± 0.003M/s | 3.413 ± 0.003M/s | 47.87 % | | 40 | 2.300 ± 0.029M/s | 3.413 ± 0.003M/s | 48.39 % | | 64 | 2.286 ± 0.001M/s | 3.410 ± 0.001M/s | 49.16 % | | 128 | 2.250 ± 0.001M/s | 3.404 ± 0.001M/s | 51.28 % | | 256 | 2.173 ± 0.001M/s | 3.383 ± 0.001M/s | 55.68 % | | 512 | 2.023 ± 0.055M/s | 3.340 ± 0.001M/s | 65.10 % | +-------------+------------------+------------------+-------------+ ARM64: +-------------+------------------+------------------+-------------+ | Buffer Size | Before | After | Improvement | +-------------+------------------+------------------+-------------+ | 4 | 1.397 ± 0.005M/s | 1.493 ± 0.005M/s | 6.87 % | | 8 | 1.402 ± 0.002M/s | 1.489 ± 0.002M/s | 6.20 % | | 16 | 1.391 ± 0.001M/s | 1.481 ± 0.001M/s | 6.47 % | | 20 | 1.379 ± 0.001M/s | 1.477 ± 0.001M/s | 7.10 % | | 32 | 1.358 ± 0.001M/s | 1.469 ± 0.002M/s | 8.17 % | | 40 | 1.339 ± 0.001M/s | 1.462 ± 0.002M/s | 9.18 % | | 64 | 1.302 ± 0.002M/s | 1.449 ± 0.003M/s | 11.29 % | | 128 | 1.214 ± 0.001M/s | 1.443 ± 0.003M/s | 18.86 % | | 256 | 1.080 ± 0.001M/s | 1.423 ± 0.001M/s | 31.75 % | | 512 | 0.887 ± 0.001M/s | 1.411 ± 0.002M/s | 59.07 % | +-------------+------------------+------------------+-------------+ Patch 5 adds a selftest for this helper to verify the results produced by this helper in multiple modes and edge cases. Patch 3 reverts a hack that was done to make the selftest pass on all architectures. Puranjay Mohan (5): net: checksum: move from32to16() to generic header bpf: bpf_csum_diff: optimize and homogenize for all archs selftests/bpf: don't mask result of bpf_csum_diff() in test_verifier selftests/bpf: Add benchmark for bpf_csum_diff() helper selftests/bpf: Add a selftest for bpf_csum_diff() arch/parisc/lib/checksum.c | 13 +- include/net/checksum.h | 6 + lib/checksum.c | 11 +- net/core/filter.c | 37 +- tools/testing/selftests/bpf/Makefile | 2 + tools/testing/selftests/bpf/bench.c | 4 + .../selftests/bpf/benchs/bench_csum_diff.c | 164 +++++++ .../bpf/benchs/run_bench_csum_diff.sh | 10 + .../selftests/bpf/prog_tests/test_csum_diff.c | 408 ++++++++++++++++++ .../selftests/bpf/progs/csum_diff_bench.c | 25 ++ .../selftests/bpf/progs/csum_diff_test.c | 42 ++ .../bpf/progs/verifier_array_access.c | 3 +- 12 files changed, 674 insertions(+), 51 deletions(-) create mode 100644 tools/testing/selftests/bpf/benchs/bench_csum_diff.c create mode 100755 tools/testing/selftests/bpf/benchs/run_bench_csum_diff.sh create mode 100644 tools/testing/selftests/bpf/prog_tests/test_csum_diff.c create mode 100644 tools/testing/selftests/bpf/progs/csum_diff_bench.c create mode 100644 tools/testing/selftests/bpf/progs/csum_diff_test.c