From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 81273471AD; Wed, 7 Jan 2026 18:04:34 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 001C24028E; Wed, 7 Jan 2026 18:04:33 +0100 (CET) Received: from mail-qv1-f50.google.com (mail-qv1-f50.google.com [209.85.219.50]) by mails.dpdk.org (Postfix) with ESMTP id C55934021E for ; Wed, 7 Jan 2026 18:04:32 +0100 (CET) Received: by mail-qv1-f50.google.com with SMTP id 6a1803df08f44-88a3bba9fd4so20931296d6.2 for ; Wed, 07 Jan 2026 09:04:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1767805472; x=1768410272; darn=dpdk.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=UrhTPJPDWo85DvdcV2OLaC71w8aw7CCFZHzXtWl6ikY=; b=edvbIl+tSYHfifrkvhaFBeOkHBnJjtpYCnBV4vRRMIHvXCrT13oFuqBLlxmMtaBdcI RSFlBiLTa0o0QSTCbdPdOXL2yb/b70gq3ed9uwv1TiyK2OLuQF6HxjtWH2/WDlxdseJ8 UpIuvHxBYsxV/iFQap4s2u2Ma6JZoY44+HrsIvnIFAp+nDSJ03OLSJNc/0SYj+EW/Ck/ BcjjjSBelkmGVGnFaPkQe55eKs90tGoXuRQL6Gh9/yW+fyG+q9zUzX+5OR6G2mNmcSaC UTBl/jStkC/KvvWIO7Bb3jr+FJScsh8QE1HWBIq0LbjEVHjPC7u48fNwfiv65Ol87QyF BOcg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767805472; x=1768410272; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=UrhTPJPDWo85DvdcV2OLaC71w8aw7CCFZHzXtWl6ikY=; b=Tv5/0Qs9LEo3xdhdX+wJhOI0FlMwTRd88OwgxD7H8N/aqvt8Z6bjS4Ul0WO1gPOWEE zZj8ithDxY5nybH4HLvCpUxzjzlHzdzulVS15abK1eegLRuaD8DbYgWpWMBTqf1QhWm1 1lOVdgnruMco/wBfuHQZCReVUZqBlz0RiY1/SloXzuT56VxnRHS7Niz0ky1XJ3E88ToL 91E/RnD/Yzehh45CIHAa1IB4rX3903LjapA4YaqYUXnC1L35A0yarnK3kuf5wRxNvV8a WCjCkpiwKgVloOkfx8WV1BvSU0Goz0VKOisl0RCUhoQwZyBKeAf4m2+9L30LUQduLFNn 4+nA== X-Gm-Message-State: AOJu0YyVRpFNTgKCPiXRUrUxIkRtb3lM56OwYtLQE+3QXsU+MUtzcF0n C7yZJi6gSoJ5b3BSva4gn7cQA6d2B/EAicUN2itZ4AQXqu36F9Uwarq/VNjCIA== X-Gm-Gg: AY/fxX5mar/FncwCMqo30/31ekYeZ51+6qKVzU7spMPKBsixOyH3QIMo9UtvbZ1zy50 DgJzmhA7lxzgfWruHw9lKSoxuA0ZeJTti06HTN8Brd2cBR3Jxx9G2As/dGJBP26rHJz0iGaB+f1 QMLJOD7ntkwBg/WSQeDY2wwnQL/tD901XRv+sO0ihcDn9OR160024/hMtaAZaYbxc1p2FHRZCNw vONuMS/dXsVSE61S+/WiE2oiAuXgVLrq0hccRfZOny70MZMHxXT1gG0bwTj6jpw23eFO0gKSuag FZ5yYVoB7X1YMdDwjyb7eRX43TPPWk209JOKde9br/SzbKTNekQLq7Y3mrnuTsrvEnj3RUWbibu hWeoMI/D0GprIymFjw01clWQDKFWw2W8J3GyeVGrgGOWqLI8aeJnS37BANcpI9FCALVaaMw7xs+ 9jHxA8hIf+ikPyQU3aip2R33gRPXVPs8792HsjOSIhN4iSK92Pfw5VhVBPGQ== X-Google-Smtp-Source: AGHT+IFy+O+cuJarXauYVIZ9etEpOfvvQ1TflomuyooRU7SCvIf9NTFn1QgdUqexNXErVAcoNEXWag== X-Received: by 2002:ad4:5968:0:b0:7e3:cc6e:3c89 with SMTP id 6a1803df08f44-89084270b69mr46853046d6.56.1767805470107; Wed, 07 Jan 2026 09:04:30 -0800 (PST) Received: from st47p01nt-relayp02.apple.com ([2601:182:b80:6a50:55a3:c8d2:e6eb:53e3]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8907725ffc7sm35980536d6.44.2026.01.07.09.04.29 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Wed, 07 Jan 2026 09:04:29 -0800 (PST) From: scott.k.mitch1@gmail.com To: dev@dpdk.org Cc: mb@smartsharesystems.com, Scott Mitchell Subject: [PATCH v3] net: optimize raw checksum computation Date: Wed, 7 Jan 2026 12:04:15 -0500 Message-Id: <20260107170415.80275-1-scott.k.mitch1@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org From: Scott Mitchell Optimize __rte_raw_cksum() by processing data in larger unrolled loops instead of iterating word-by-word. The new implementation processes 64-byte blocks (32 x uint16_t) in the hot path, followed by smaller 32/16/8/4/2-byte chunks. Uses uint32_t accumulator with explicit casts to prevent signed integer overflow and leverages unaligned_uint16_t for safe unaligned access on all platforms. Adds __rte_no_ubsan_alignment attribute to suppress false positive alignment warnings from UndefinedBehaviorSanitizer. Performance results from cksum_perf_autotest (TSC cycles/byte): Block size Before After Improvement 100 0.40-0.64 0.13-0.14 ~3-4x 1500 0.49-0.51 0.10-0.11 ~4-5x 9000 0.48-0.51 0.11-0.12 ~4x Signed-off-by: Scott Mitchell --- Changes in v3: - Added __rte_no_ubsan_alignment macro to suppress false-positive UBSAN alignment warnings when using unaligned_uint16_t - Fixed false-positive GCC maybe-uninitialized warning in rte_ip6.h exposed by optimization (can be split to separate patch once verified on CI) Changes in v2: - Fixed UndefinedBehaviorSanitizer errors by adding uint32_t casts to prevent signed integer overflow in addition chains - Restored uint32_t sum accumulator instead of uint64_t - Added 64k length to test_cksum_perf.c app/test/meson.build | 1 + app/test/test_cksum_fuzz.c | 241 +++++++++++++++++++++++++++++++++++ app/test/test_cksum_perf.c | 2 +- lib/eal/include/rte_common.h | 9 ++ lib/net/rte_cksum.h | 60 +++++++-- lib/net/rte_ip6.h | 2 +- 6 files changed, 303 insertions(+), 12 deletions(-) create mode 100644 app/test/test_cksum_fuzz.c diff --git a/app/test/meson.build b/app/test/meson.build index efec42a6bf..c92325ad58 100644 --- a/app/test/meson.build +++ b/app/test/meson.build @@ -38,6 +38,7 @@ source_file_deps = { 'test_byteorder.c': [], 'test_cfgfile.c': ['cfgfile'], 'test_cksum.c': ['net'], + 'test_cksum_fuzz.c': ['net'], 'test_cksum_perf.c': ['net'], 'test_cmdline.c': [], 'test_cmdline_cirbuf.c': [], diff --git a/app/test/test_cksum_fuzz.c b/app/test/test_cksum_fuzz.c new file mode 100644 index 0000000000..cc3c3e71e1 --- /dev/null +++ b/app/test/test_cksum_fuzz.c @@ -0,0 +1,241 @@ +/* SPDX-License-Identifier: BSD-3-Clause + * Copyright(c) 2026 Apple Inc. + */ + +#include +#include + +#include +#include +#include +#include +#include +#include + +#include "test.h" + +/* + * Fuzz test for __rte_raw_cksum optimization. + * Compares the optimized implementation against the original reference + * implementation across random data of various lengths. + */ + +#define DEFAULT_ITERATIONS 1000 +#define MAX_TEST_LEN 65536 /* 64K to match GRO frame sizes */ + +/* + * Original (reference) implementation of __rte_raw_cksum from DPDK v23.11. + * This is retained here for comparison testing against the optimized version. + */ +static inline uint32_t +__rte_raw_cksum_reference(const void *buf, size_t len, uint32_t sum) +{ + const void *end; + + for (end = RTE_PTR_ADD(buf, RTE_ALIGN_FLOOR(len, sizeof(uint16_t))); + buf != end; buf = RTE_PTR_ADD(buf, sizeof(uint16_t))) { + uint16_t v; + + memcpy(&v, buf, sizeof(uint16_t)); + sum += v; + } + + /* if length is odd, keeping it byte order independent */ + if (unlikely(len % 2)) { + uint16_t left = 0; + + memcpy(&left, end, 1); + sum += left; + } + + return sum; +} + +static void +init_random_buffer(uint8_t *buf, size_t len) +{ + size_t i; + + for (i = 0; i < len; i++) + buf[i] = (uint8_t)rte_rand(); +} + +static inline uint32_t +get_initial_sum(bool random_initial_sum) +{ + return random_initial_sum ? (rte_rand() & 0xFFFFFFFF) : 0; +} + +/* + * Test a single buffer length with specific alignment and initial sum + */ +static int +test_cksum_fuzz_length_aligned(size_t len, bool aligned, uint32_t initial_sum) +{ + uint8_t *data; + uint8_t *buf; + size_t alloc_size; + uint32_t sum_ref, sum_opt; + + if (len == 0 && !aligned) { + /* Skip unaligned test for zero length - nothing to test */ + return TEST_SUCCESS; + } + + /* Allocate exact size for aligned, +1 for unaligned offset */ + alloc_size = aligned ? len : len + 1; + if (alloc_size == 0) + alloc_size = 1; /* rte_malloc doesn't like 0 */ + + data = rte_malloc(NULL, alloc_size, 64); + if (data == NULL) { + printf("Failed to allocate %zu bytes\n", alloc_size); + return TEST_FAILED; + } + + buf = aligned ? data : (data + 1); + + init_random_buffer(buf, len); + + sum_ref = __rte_raw_cksum_reference(buf, len, initial_sum); + sum_opt = __rte_raw_cksum(buf, len, initial_sum); + + if (sum_ref != sum_opt) { + printf("MISMATCH at len=%zu aligned='%s' initial_sum=0x%08x ref=0x%08x opt=0x%08x\n", + len, aligned ? "aligned" : "unaligned", + initial_sum, sum_ref, sum_opt); + rte_hexdump(stdout, "failing buffer", buf, len); + rte_free(data); + return TEST_FAILED; + } + + rte_free(data); + return TEST_SUCCESS; +} + +/* + * Test a length with both alignments + */ +static int +test_cksum_fuzz_length(size_t len, uint32_t initial_sum) +{ + int rc; + + /* Test aligned */ + rc = test_cksum_fuzz_length_aligned(len, true, initial_sum); + if (rc != TEST_SUCCESS) + return rc; + + /* Test unaligned */ + rc = test_cksum_fuzz_length_aligned(len, false, initial_sum); + + return rc; +} + +/* + * Test specific edge case lengths + */ +static int +test_cksum_fuzz_edge_cases(void) +{ + /* Edge case lengths that might trigger bugs */ + static const size_t edge_lengths[] = { + 0, 1, 2, 3, 4, 5, 6, 7, 8, + 15, 16, 17, + 31, 32, 33, + 63, 64, 65, + 127, 128, 129, + 255, 256, 257, + 511, 512, 513, + 1023, 1024, 1025, + 1500, 1501, /* MTU boundaries */ + 2047, 2048, 2049, + 4095, 4096, 4097, + 8191, 8192, 8193, + 16383, 16384, 16385, + 32767, 32768, 32769, + 65534, 65535, 65536 /* 64K GRO boundaries */ + }; + unsigned int i; + int rc; + + printf("Testing edge case lengths...\n"); + + for (i = 0; i < RTE_DIM(edge_lengths); i++) { + /* Test with zero initial sum */ + rc = test_cksum_fuzz_length(edge_lengths[i], 0); + if (rc != TEST_SUCCESS) + return rc; + + /* Test with random initial sum */ + rc = test_cksum_fuzz_length(edge_lengths[i], get_initial_sum(true)); + if (rc != TEST_SUCCESS) + return rc; + } + + return TEST_SUCCESS; +} + +/* + * Test random lengths with optional random initial sums + */ +static int +test_cksum_fuzz_random(unsigned int iterations, bool random_initial_sum) +{ + unsigned int i; + int rc; + + printf("Testing random lengths (0-%d)%s...\n", MAX_TEST_LEN, + random_initial_sum ? " with random initial sums" : ""); + + for (i = 0; i < iterations; i++) { + size_t len = rte_rand() % (MAX_TEST_LEN + 1); + + rc = test_cksum_fuzz_length(len, get_initial_sum(random_initial_sum)); + if (rc != TEST_SUCCESS) { + printf("Failed at len=%zu\n", len); + return rc; + } + } + + return TEST_SUCCESS; +} + +static int +test_cksum_fuzz(void) +{ + int rc; + unsigned int iterations = DEFAULT_ITERATIONS; + + printf("### __rte_raw_cksum optimization fuzz test ###\n"); + printf("Iterations per test: %u\n\n", iterations); + + /* Test edge cases */ + rc = test_cksum_fuzz_edge_cases(); + if (rc != TEST_SUCCESS) { + printf("Edge case test FAILED\n"); + return rc; + } + printf("Edge case test PASSED\n\n"); + + /* Test random lengths with zero initial sum */ + rc = test_cksum_fuzz_random(iterations, false); + if (rc != TEST_SUCCESS) { + printf("Random length test FAILED\n"); + return rc; + } + printf("Random length test PASSED\n\n"); + + /* Test random lengths with random initial sums */ + rc = test_cksum_fuzz_random(iterations, true); + if (rc != TEST_SUCCESS) { + printf("Random initial sum test FAILED\n"); + return rc; + } + printf("Random initial sum test PASSED\n\n"); + + printf("All fuzz tests PASSED!\n"); + return TEST_SUCCESS; +} + +REGISTER_FAST_TEST(cksum_fuzz_autotest, true, true, test_cksum_fuzz); diff --git a/app/test/test_cksum_perf.c b/app/test/test_cksum_perf.c index 0b919cd59f..6b1d4589e0 100644 --- a/app/test/test_cksum_perf.c +++ b/app/test/test_cksum_perf.c @@ -15,7 +15,7 @@ #define NUM_BLOCKS 10 #define ITERATIONS 1000000 -static const size_t data_sizes[] = { 20, 21, 100, 101, 1500, 1501 }; +static const size_t data_sizes[] = { 20, 21, 100, 101, 1500, 1501, 9000, 9001, 65536, 65537 }; static __rte_noinline uint16_t do_rte_raw_cksum(const void *buf, size_t len) diff --git a/lib/eal/include/rte_common.h b/lib/eal/include/rte_common.h index 9e7d84f929..37a36a1b22 100644 --- a/lib/eal/include/rte_common.h +++ b/lib/eal/include/rte_common.h @@ -546,6 +546,15 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void) #define __rte_no_asan #endif +/** + * Disable UndefinedBehaviorSanitizer alignment checks + */ +#if defined(RTE_TOOLCHAIN_GCC) || defined(RTE_TOOLCHAIN_CLANG) +#define __rte_no_ubsan_alignment __attribute__((no_sanitize("alignment"))) +#else +#define __rte_no_ubsan_alignment +#endif + /*********** Macros for pointer arithmetic ********/ /** diff --git a/lib/net/rte_cksum.h b/lib/net/rte_cksum.h index a8e8927952..d6e313dea5 100644 --- a/lib/net/rte_cksum.h +++ b/lib/net/rte_cksum.h @@ -39,24 +39,64 @@ extern "C" { * @return * sum += Sum of all words in the buffer. */ +__rte_no_ubsan_alignment static inline uint32_t __rte_raw_cksum(const void *buf, size_t len, uint32_t sum) { - const void *end; + /* Process in 64 byte blocks (32 x uint16_t). */ + /* Always process as uint16_t chunks to preserve overflow/carry. */ + const void *end = RTE_PTR_ADD(buf, RTE_ALIGN_FLOOR(len, 64)); + while (buf != end) { + const unaligned_uint16_t *p16 = (const unaligned_uint16_t *)buf; + sum += (uint32_t)p16[0] + p16[1] + p16[2] + p16[3] + + p16[4] + p16[5] + p16[6] + p16[7] + + p16[8] + p16[9] + p16[10] + p16[11] + + p16[12] + p16[13] + p16[14] + p16[15] + + p16[16] + p16[17] + p16[18] + p16[19] + + p16[20] + p16[21] + p16[22] + p16[23] + + p16[24] + p16[25] + p16[26] + p16[27] + + p16[28] + p16[29] + p16[30] + p16[31]; + buf = RTE_PTR_ADD(buf, 64); + } - for (end = RTE_PTR_ADD(buf, RTE_ALIGN_FLOOR(len, sizeof(uint16_t))); - buf != end; buf = RTE_PTR_ADD(buf, sizeof(uint16_t))) { - uint16_t v; + if (len & 32) { + const unaligned_uint16_t *p16 = (const unaligned_uint16_t *)buf; + sum += (uint32_t)p16[0] + p16[1] + p16[2] + p16[3] + + p16[4] + p16[5] + p16[6] + p16[7] + + p16[8] + p16[9] + p16[10] + p16[11] + + p16[12] + p16[13] + p16[14] + p16[15]; + buf = RTE_PTR_ADD(buf, 32); + } - memcpy(&v, buf, sizeof(uint16_t)); - sum += v; + if (len & 16) { + const unaligned_uint16_t *p16 = (const unaligned_uint16_t *)buf; + sum += (uint32_t)p16[0] + p16[1] + p16[2] + p16[3] + + p16[4] + p16[5] + p16[6] + p16[7]; + buf = RTE_PTR_ADD(buf, 16); } - /* if length is odd, keeping it byte order independent */ - if (unlikely(len % 2)) { - uint16_t left = 0; + if (len & 8) { + const unaligned_uint16_t *p16 = (const unaligned_uint16_t *)buf; + sum += (uint32_t)p16[0] + p16[1] + p16[2] + p16[3]; + buf = RTE_PTR_ADD(buf, 8); + } - memcpy(&left, end, 1); + if (len & 4) { + const unaligned_uint16_t *p16 = (const unaligned_uint16_t *)buf; + sum += (uint32_t)p16[0] + p16[1]; + buf = RTE_PTR_ADD(buf, 4); + } + + if (len & 2) { + const unaligned_uint16_t *p16 = (const unaligned_uint16_t *)buf; + sum += *p16; + buf = RTE_PTR_ADD(buf, 2); + } + + /* If length is odd use memcpy for byte order independence */ + if (len & 1) { + uint16_t left = 0; + memcpy(&left, buf, 1); sum += left; } diff --git a/lib/net/rte_ip6.h b/lib/net/rte_ip6.h index d1abf1f5d5..af65a39815 100644 --- a/lib/net/rte_ip6.h +++ b/lib/net/rte_ip6.h @@ -564,7 +564,7 @@ rte_ipv6_phdr_cksum(const struct rte_ipv6_hdr *ipv6_hdr, uint64_t ol_flags) struct { rte_be32_t len; /* L4 length. */ rte_be32_t proto; /* L4 protocol - top 3 bytes must be zero */ - } psd_hdr; + } psd_hdr = {0}; /* Empty initializer avoids false-positive maybe-uninitialized warning */ psd_hdr.proto = (uint32_t)(ipv6_hdr->proto << 24); if (ol_flags & (RTE_MBUF_F_TX_TCP_SEG | RTE_MBUF_F_TX_UDP_SEG)) -- 2.39.5 (Apple Git-154)