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 9864F471E7; Sun, 11 Jan 2026 17:06:35 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id E256D40647; Sun, 11 Jan 2026 17:06:33 +0100 (CET) Received: from mail-qv1-f42.google.com (mail-qv1-f42.google.com [209.85.219.42]) by mails.dpdk.org (Postfix) with ESMTP id D668540647 for ; Sun, 11 Jan 2026 17:06:32 +0100 (CET) Received: by mail-qv1-f42.google.com with SMTP id 6a1803df08f44-890228ed342so61667606d6.2 for ; Sun, 11 Jan 2026 08:06:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1768147592; x=1768752392; darn=dpdk.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=kSp+9y59pGtxRKQ/dGmE1wrht7tcwG4rui+njSbJWcI=; b=JmdIyplkZpSAsX3mP9ZY6JQw+7OKMjDzVpmMC53WRPxUuRt4ywST81wIdshxK1WkYd Is3F2I56GAzz0bTepz87ac/ULOBgZUi3tLx9WJ2oyY3f3K8G2h5GzikHoxBV13ZZeILb McXAdJEp/xjNNaLqPCdOGqEGOcEkQCEdKfbF17cAiV4PBVMpEkGST0F51q8SjVrrdS6m Qgy8qUlnNmQjbOvcgwAIPdwm/QcIIpJ1AvsdVQSqBt/hdGtB0ui5E9FoIIEOQzEkablw HWkl89A3VukI6m6FjphL9qLgnncBXMA55S9CEbY13CtK+gNGe7gJasFaOVDrW6Ub2waU mrnA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1768147592; x=1768752392; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=kSp+9y59pGtxRKQ/dGmE1wrht7tcwG4rui+njSbJWcI=; b=SUfydi8rpUvBKtLgYBTH2USIFwaRpnFcqZ842skmpTnRNYzWPR3YYY6jkmSZsfOLOZ rzRhVgAPwzFx+RILQJdoxrPa4BpY1VgFuS/it69d4G8HZnG8pfRPnh1hOocFudo3uQSm gT68DviYEmOL8aSPRTIrrHato1AZzukGro0YFGvYFSrvexrEMKUygupDn601cXRJqazi TOKEC8/RLNzDpt6F89hKj6Y3qgPwwkQMJ5ouDFm21uL5bwhkIYvEahigIKFl7+3rGna9 dfEPwq5c+lj09tLKUnzXhv7W1r+h5k5pCpb9ICvSsto7ty520HsT6mWwiTE18ETr7ovG kpvg== X-Gm-Message-State: AOJu0YxvJuxoOobgC8YEo6mL9G7qtiXbU/1631gBDciOL5IO51XGLzxZ VxtSBl9hcCGkn9MFmOgtwva+uuJVuTAbIIuzDPF3ljy82iPJW0EJ+Koc+sr2Nw== X-Gm-Gg: AY/fxX5ye3NxWnuriTZrpbGgf98O4s+3Z5SaV2tX3tDn7TZFSHsde2JWJlSV2Rcek/t kbgDiRQwtQ6rDBZgHNnxFPfPbtAAd7zJkxwvdWCRISyEkb0Z4WkpMS7eP5HB0FI+rG9jkeHhVGs AXLOELQBtgauAGCqJiTvpdwuwB9pa4oJLtcb1IgTTAnJkr9d2F9JnQTMA/5J509SxjOzphJxLIL mCFPhP2TNpwpPa2QxEhlcjYEm6CqVqYEyQzHh4y/5/nnn59vZTT9Mo3a3wpazjKBxs1dw7KAU9/ rZ6ukt6Pj8IOYK4dEzSvPLv/zuA2Y4994TcHdzjfUrceVY6VcIURhlXdnzRjH6yT5o90joX/0E3 eJNZPb/7gRp960ZwSrZDRVOj8ZCfEm0fVynue5ujl9geQN5bC89IFYlEfAShpD69wDJ4ioV7izg oLpMz7mSPo33DSaml4S3k4IqU6URHL3nt87TaK0GQ2JKyVLuOlL/ZKee24zia6 X-Google-Smtp-Source: AGHT+IEr1fJ3eyg15LX3kK062AeJFU+kLUky/fRzhBxUkXjfx13Zk6e2Qtl/Lnl/NPIbjjb0wbvSgg== X-Received: by 2002:a05:622a:1445:b0:4f1:e97b:2896 with SMTP id d75a77b69052e-4ffb499d264mr209850821cf.46.1768147591767; Sun, 11 Jan 2026 08:06:31 -0800 (PST) Received: from st57p01nt-relayp02.apple.com ([2600:1000:b19c:b9d9:b0a4:2ee1:3986:5e9d]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-4ffa8d3d34fsm106575561cf.4.2026.01.11.08.06.31 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Sun, 11 Jan 2026 08:06:31 -0800 (PST) From: scott.k.mitch1@gmail.com To: dev@dpdk.org Cc: mb@smartsharesystems.com, stephen@networkplumber.org, Scott Mitchell Subject: [PATCH v4 1/2] eal: RTE_PTR_ADD/SUB char* for compiler optimizations Date: Sun, 11 Jan 2026 11:06:25 -0500 Message-Id: <20260111160626.2103-2-scott.k.mitch1@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20260111160626.2103-1-scott.k.mitch1@gmail.com> References: <20260111160626.2103-1-scott.k.mitch1@gmail.com> 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 Modify RTE_PTR_ADD and RTE_PTR_SUB to use char* pointer arithmetic instead of uintptr_t casts when operating on pointer types. This enables better compiler optimization, particularly for Clang which can now recognize simple pointer patterns and apply vectorization, loop unrolling, and improved assembly. The implementation uses C11 _Generic to dispatch based on input type: - Integer types (int, uint64_t, etc.) continue using uintptr_t arithmetic for API compatibility - Pointer types use char* arithmetic, with const-qualified pointers using const char* internally to preserve optimization hints Example use case which benefits is __rte_raw_cksum. Performance results from cksum_perf_autotest on Intel Xeon (Cascade Lake, AVX-512) built with Clang 18.1 (TSC cycles/byte): Block size Before After Improvement 100 0.40 0.24 ~40% 1500 0.50 0.06 ~8x 9000 0.49 0.06 ~8x Signed-off-by: Scott Mitchell --- app/test/meson.build | 1 + app/test/test_ptr_add_sub.c | 190 +++++++++++++++++++++++++++++++++++ lib/eal/include/rte_common.h | 60 +++++++++++ 3 files changed, 251 insertions(+) create mode 100644 app/test/test_ptr_add_sub.c diff --git a/app/test/meson.build b/app/test/meson.build index efec42a6bf..80a19d65ba 100644 --- a/app/test/meson.build +++ b/app/test/meson.build @@ -152,6 +152,7 @@ source_file_deps = { 'test_power_intel_uncore.c': ['power', 'power_intel_uncore'], 'test_power_kvm_vm.c': ['power', 'power_kvm_vm'], 'test_prefetch.c': [], + 'test_ptr_add_sub.c': [], 'test_ptr_compress.c': ['ptr_compress'], 'test_rand_perf.c': [], 'test_rawdev.c': ['rawdev', 'bus_vdev', 'raw_skeleton'], diff --git a/app/test/test_ptr_add_sub.c b/app/test/test_ptr_add_sub.c new file mode 100644 index 0000000000..ef449ca9af --- /dev/null +++ b/app/test/test_ptr_add_sub.c @@ -0,0 +1,190 @@ +/* SPDX-License-Identifier: BSD-3-Clause + * Copyright(c) 2026 Apple Inc. + */ + +#include "test.h" +#include +#include + +#include + +/* Test all C11 standard integer types */ +static int +test_ptr_add_sub_integer_types(void) +{ + unsigned long long ull = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(ull, 100), 0x1064, + "RTE_PTR_ADD failed for unsigned long long"); + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_SUB(ull, 100), 0x1000 - 100, + "RTE_PTR_SUB failed for unsigned long long"); + + long long ll = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(ll, 100), 0x1064, + "RTE_PTR_ADD failed for long long"); + + unsigned long ul = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(ul, 100), 0x1064, + "RTE_PTR_ADD failed for unsigned long"); + + long l = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(l, 100), 0x1064, + "RTE_PTR_ADD failed for long"); + + unsigned int ui = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(ui, 100), 0x1064, + "RTE_PTR_ADD failed for unsigned int"); + + int i = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(i, 100), 0x1064, + "RTE_PTR_ADD failed for int"); + + unsigned short us = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(us, 100), 0x1064, + "RTE_PTR_ADD failed for unsigned short"); + + short s = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(s, 100), 0x1064, + "RTE_PTR_ADD failed for short"); + + unsigned char uc = 100; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(uc, 50), 150, + "RTE_PTR_ADD failed for unsigned char"); + + signed char sc = 100; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(sc, 50), 150, + "RTE_PTR_ADD failed for signed char"); + + char c = 100; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(c, 50), 150, + "RTE_PTR_ADD failed for char"); + + _Bool b = 1; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(b, 99), 100, + "RTE_PTR_ADD failed for _Bool"); + + bool b2 = true; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(b2, 99), 100, + "RTE_PTR_ADD failed for bool"); + + return 0; +} + +/* Test pointer types including const correctness */ +static int +test_ptr_add_sub_pointer_types(void) +{ + char buffer[256]; + void *result; + + /* Test void* and const void* */ + void *vp = buffer; + result = RTE_PTR_ADD(vp, 100); + TEST_ASSERT_EQUAL(result, (void *)(buffer + 100), + "RTE_PTR_ADD failed for void*"); + result = RTE_PTR_SUB(vp, 50); + TEST_ASSERT_EQUAL(result, (void *)(buffer - 50), + "RTE_PTR_SUB failed for void*"); + + const void *cvp = buffer; + result = RTE_PTR_ADD(cvp, 100); + TEST_ASSERT_EQUAL(result, (void *)(buffer + 100), + "RTE_PTR_ADD failed for const void*"); + result = RTE_PTR_SUB(cvp, 50); + TEST_ASSERT_EQUAL(result, (void *)(buffer - 50), + "RTE_PTR_SUB failed for const void*"); + + /* Test char* and const char* */ + char *cp = buffer; + result = RTE_PTR_ADD(cp, 100); + TEST_ASSERT_EQUAL(result, (void *)(buffer + 100), + "RTE_PTR_ADD failed for char*"); + result = RTE_PTR_SUB(cp, 50); + TEST_ASSERT_EQUAL(result, (void *)(buffer - 50), + "RTE_PTR_SUB failed for char*"); + + const char *ccp = buffer; + result = RTE_PTR_ADD(ccp, 100); + TEST_ASSERT_EQUAL(result, (void *)(buffer + 100), + "RTE_PTR_ADD failed for const char*"); + result = RTE_PTR_SUB(ccp, 50); + TEST_ASSERT_EQUAL(result, (void *)(buffer - 50), + "RTE_PTR_SUB failed for const char*"); + + /* Test uint32_t* and const uint32_t* */ + uint32_t *u32p = (uint32_t *)buffer; + result = RTE_PTR_ADD(u32p, 100); + TEST_ASSERT_EQUAL(result, (void *)(buffer + 100), + "RTE_PTR_ADD failed for uint32_t*"); + result = RTE_PTR_SUB(u32p, 50); + TEST_ASSERT_EQUAL(result, (void *)(buffer - 50), + "RTE_PTR_SUB failed for uint32_t*"); + + const uint32_t *cu32p = (const uint32_t *)buffer; + result = RTE_PTR_ADD(cu32p, 100); + TEST_ASSERT_EQUAL(result, (void *)(buffer + 100), + "RTE_PTR_ADD failed for const uint32_t*"); + result = RTE_PTR_SUB(cu32p, 50); + TEST_ASSERT_EQUAL(result, (void *)(buffer - 50), + "RTE_PTR_SUB failed for const uint32_t*"); + + /* Verify assigning to const pointer works (adding const is safe) */ + const void *result_const = RTE_PTR_ADD(cvp, 100); + TEST_ASSERT_EQUAL(result_const, (const void *)(buffer + 100), + "RTE_PTR_ADD failed when assigning to const void*"); + + return 0; +} + +/* Test that typedefs resolve to native types correctly */ +static int +test_ptr_add_sub_typedefs(void) +{ + uint64_t u64 = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(u64, 100), 0x1064, + "RTE_PTR_ADD failed for uint64_t"); + + uint32_t u32 = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(u32, 100), 0x1064, + "RTE_PTR_ADD failed for uint32_t"); + + uint16_t u16 = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(u16, 100), 0x1064, + "RTE_PTR_ADD failed for uint16_t"); + + uint8_t u8 = 100; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(u8, 50), 150, + "RTE_PTR_ADD failed for uint8_t"); + + uintptr_t uptr = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(uptr, 100), 0x1064, + "RTE_PTR_ADD failed for uintptr_t"); + + size_t sz = 0x1000; + TEST_ASSERT_EQUAL((uintptr_t)RTE_PTR_ADD(sz, 100), 0x1064, + "RTE_PTR_ADD failed for size_t"); + + return 0; +} + +/* Main test function that runs all subtests */ +static int +test_ptr_add_sub(void) +{ + int ret; + + ret = test_ptr_add_sub_integer_types(); + if (ret != 0) + return ret; + + ret = test_ptr_add_sub_pointer_types(); + if (ret != 0) + return ret; + + ret = test_ptr_add_sub_typedefs(); + if (ret != 0) + return ret; + + return 0; +} + +REGISTER_FAST_TEST(ptr_add_sub_autotest, true, true, test_ptr_add_sub); diff --git a/lib/eal/include/rte_common.h b/lib/eal/include/rte_common.h index 9e7d84f929..1ae239b43a 100644 --- a/lib/eal/include/rte_common.h +++ b/lib/eal/include/rte_common.h @@ -551,12 +551,72 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void) /** * add a byte-value offset to a pointer */ +#ifndef RTE_TOOLCHAIN_MSVC +#define RTE_PTR_ADD(ptr, x) \ + (__extension__ ({ \ + /* Diagnostics suppressed for internal macro operations only. \ + * Compiler type-checks all _Generic branches even when unselected, \ + * triggering warnings with no external impact. */ \ + __rte_diagnostic_push \ + __rte_diagnostic_ignored_wcast_qual \ + /* Uses uintptr_t arithmetic for integer types (API compatibility), \ + * and char* arithmetic for pointer types (enables optimization). */ \ + __auto_type _ptr_result = _Generic((ptr), \ + unsigned long long: ((void *)((uintptr_t)(ptr) + (x))), \ + long long: ((void *)((uintptr_t)(ptr) + (x))), \ + unsigned long: ((void *)((uintptr_t)(ptr) + (x))), \ + long: ((void *)((uintptr_t)(ptr) + (x))), \ + unsigned int: ((void *)((uintptr_t)(ptr) + (x))), \ + int: ((void *)((uintptr_t)(ptr) + (x))), \ + unsigned short: ((void *)((uintptr_t)(ptr) + (x))), \ + short: ((void *)((uintptr_t)(ptr) + (x))), \ + unsigned char: ((void *)((uintptr_t)(ptr) + (x))), \ + signed char: ((void *)((uintptr_t)(ptr) + (x))), \ + char: ((void *)((uintptr_t)(ptr) + (x))), \ + _Bool: ((void *)((uintptr_t)(ptr) + (x))), \ + default: ((void *)((char *)(ptr) + (x))) \ + ); \ + __rte_diagnostic_pop \ + _ptr_result; \ + })) +#else #define RTE_PTR_ADD(ptr, x) ((void*)((uintptr_t)(ptr) + (x))) +#endif /** * subtract a byte-value offset from a pointer */ +#ifndef RTE_TOOLCHAIN_MSVC +#define RTE_PTR_SUB(ptr, x) \ + (__extension__ ({ \ + /* Diagnostics suppressed for internal macro operations only. \ + * Compiler type-checks all _Generic branches even when unselected, \ + * triggering warnings with no external impact. */ \ + __rte_diagnostic_push \ + __rte_diagnostic_ignored_wcast_qual \ + /* Uses uintptr_t arithmetic for integer types (API compatibility), \ + * and char* arithmetic for pointer types (enables optimization). */ \ + __auto_type _ptr_result = _Generic((ptr), \ + unsigned long long: ((void *)((uintptr_t)(ptr) - (x))), \ + long long: ((void *)((uintptr_t)(ptr) - (x))), \ + unsigned long: ((void *)((uintptr_t)(ptr) - (x))), \ + long: ((void *)((uintptr_t)(ptr) - (x))), \ + unsigned int: ((void *)((uintptr_t)(ptr) - (x))), \ + int: ((void *)((uintptr_t)(ptr) - (x))), \ + unsigned short: ((void *)((uintptr_t)(ptr) - (x))), \ + short: ((void *)((uintptr_t)(ptr) - (x))), \ + unsigned char: ((void *)((uintptr_t)(ptr) - (x))), \ + signed char: ((void *)((uintptr_t)(ptr) - (x))), \ + char: ((void *)((uintptr_t)(ptr) - (x))), \ + _Bool: ((void *)((uintptr_t)(ptr) - (x))), \ + default: ((void *)((char *)(ptr) - (x))) \ + ); \ + __rte_diagnostic_pop \ + _ptr_result; \ + })) +#else #define RTE_PTR_SUB(ptr, x) ((void *)((uintptr_t)(ptr) - (x))) +#endif /** * get the difference between two pointer values, i.e. how far apart -- 2.39.5 (Apple Git-154)