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 mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by smtp.lore.kernel.org (Postfix) with ESMTP id ABD46D3CC82 for ; Wed, 14 Jan 2026 21:58:10 +0000 (UTC) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id B5DB24064A; Wed, 14 Jan 2026 22:58:09 +0100 (CET) Received: from mail-dl1-f47.google.com (mail-dl1-f47.google.com [74.125.82.47]) by mails.dpdk.org (Postfix) with ESMTP id 0C1764027D for ; Wed, 14 Jan 2026 22:58:08 +0100 (CET) Received: by mail-dl1-f47.google.com with SMTP id a92af1059eb24-12331482b8fso768291c88.1 for ; Wed, 14 Jan 2026 13:58:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1768427887; x=1769032687; 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=EQ4IPCbs2WpVsBJw+ZL/Vw5dAq+dIZdICU6N3uvzliM=; b=Inx862K3QuS8/rJLJp9EJUcwoHCWgIAkcidaNsHD8e2ukfDbWeBINrgZt3RSHiVMNV 0/D5/BExJ0UYRiCRrHYOoFkxBhj/CHIteTVrUDgsYKaGaM1CHSY7mn5x+n9sSlFtOdfM 3wN+OyJLT5mwonQwKuZIkXr4EV+VY8oNkwTk7K/sgw+vKP6JF+CZaVKZ1YVbmLj8ZA2S oQ8p1LdhFhnwLuK1xg6bEGgkakUpk210aMKH7KzOvmfebS31UO6Js2e1FYJ8UzEua4Gl Mf7hpALgnqBKXwWb4/lXITWL+h4sdgIcTA1YPW1GF09vgx1GnNtuwU7RomimDuEgGiKq ydyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1768427887; x=1769032687; 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=EQ4IPCbs2WpVsBJw+ZL/Vw5dAq+dIZdICU6N3uvzliM=; b=KeM92HSzW11byBq58ndogJ7oI1HP050nZsHfPU3LacWUqbWlOIq03t3/asK5v65JU+ MlITGZK/EV4l+wpiylKFx/H7/ENDw/zOZ2pk2suUGOzafY1/ENHNKWic9u5exkRxgp4+ zhsFkqHzW8l1zwdYF0Le/cExA+AIhO3qme1DPpAVaCx7n6S9c9sLD4weii7LIEOsLdzT GS29vKbB3B+uZU6yJc37LBmhHigxn+8LNW1eL9GZmC7Ff2v40Cdx62oTl6vlXLM38DxJ mRblrRCufoDyrMr1gDc9wgZ4TiavudnO9My9pBgjU5yQjRfLqkXkGafCb+yB/x++4AT1 8Luw== X-Gm-Message-State: AOJu0YzCXUDjIEbcIXpzeedpmu3EnrslqJh63Qf9xBFus3vqEeXOyonU YEofzRCMVmMEOgmX1sqrONKz2/XzFSgELzhQg26hOhGj8yGKajg4/7eGe63gNQ== X-Gm-Gg: AY/fxX4GGOCUbJZr2xFDIJzqYUL75RY8D32RztpS1cc6Te7+S0ym2Bvj79jaAThk4J4 VXI7BIAoX6Zma1thJbCIhDjuQi5sx6opz4Jt+CzPTzk1K3VurayjoRnq4+6yptH2SoRE776R1Vh iia7s6I2kRy/7Gvqf/DVW9V0saaA2GB8GeintBXYBr5OLbCyT/+cEkVz4wWlLIEkmPwztYY+YTp cT4lkSxvD3P0CKm62NBUW0kn4fZN+uEhLb0bnF3m7rUVBlnpmDUpizhtYW9GOrR5VKhZAP5PBaM GgTYohHJsCfKK/gNxbqYoDYmgfSQk36Rcn3geZl4gvKQWyCTy7Dltd7phlkddtte7klhsoQ/mDc N7usgr3pakJzwl/aZ7BgzldllFRrImKxflammkPvjCu+g47sb3gV8I5rdECxMfnBVY4owpftsNo 35Xv7mUQiSiTXBcLUhL6iqGYbd3jX6lBa/w7lQ1CvZwyR6ab9k/g== X-Received: by 2002:a05:7022:1709:b0:123:2dd0:10bc with SMTP id a92af1059eb24-123376cc879mr2661250c88.10.1768427886439; Wed, 14 Jan 2026 13:58:06 -0800 (PST) Received: from mr41p01nt-relayp01.apple.com ([17.199.85.102]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-121f248c246sm32208783c88.11.2026.01.14.13.58.05 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Wed, 14 Jan 2026 13:58:06 -0800 (PST) From: scott.k.mitch1@gmail.com To: dev@dpdk.org Cc: mb@smartsharesystems.com, stephen@networkplumber.org, bruce.richardson@intel.com, Scott Mitchell Subject: [PATCH v7] eal: RTE_PTR_ADD/SUB char* for compiler optimizations Date: Wed, 14 Jan 2026 13:56:48 -0800 Message-Id: <20260114215648.47820-1-scott.k.mitch1@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20260114160750.12945-1-scott.k.mitch1@gmail.com> References: <20260114160750.12945-1-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 on Clang instead of uintptr_t casts. Benefits of this approach: - API compatibility: works for both integer and pointer inputs - Retains simple macros: no pragmas, no _Generic - Enables Clang optimizations: Clang can now unroll and vectorize pointer loops. GCC uses uintptr_t to avoid false positive warnings. 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 --- v7: - Fix tests: use TEST_BUFFER_SIZE macro for buffer allocation - Fix tests: ADD then SUB same amount to avoid out-of-bounds pointer arithmetic - All RTE_PTR_SUB tests now verify round-trip (ADD+SUB returns to original) v6: - Make char* optimization Clang-only to avoid GCC false positive warnings - Improve tests: use named constants instead of magic numbers - Improve tests: use void* casts on expected values instead of uintptr_t on results v5: - Initial implementation with char* arithmetic for all compilers v4: - Used _Generic for type-based dispatch with char* casts - Had warnings on both Clang and GCC due to _Generic type-checking all branches --- app/test/meson.build | 1 + app/test/test_ptr_add_sub.c | 197 +++++++++++++++++++++++++++++++++++ lib/eal/include/rte_common.h | 14 ++- 3 files changed, 208 insertions(+), 4 deletions(-) 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..2956eabeb3 --- /dev/null +++ b/app/test/test_ptr_add_sub.c @@ -0,0 +1,197 @@ +/* SPDX-License-Identifier: BSD-3-Clause + * Copyright(c) 2026 Apple Inc. + */ + +#include "test.h" +#include +#include + +#include + +/* Test constants for large integer types (16-bit and wider) */ +#define TEST_INITVAL_LARGE 0x1000 +#define TEST_INCREMENT_LARGE 100 +#define TEST_RETVAL_LARGE ((void *)0x1064) +#define TEST_SUBVAL_LARGE ((void *)(TEST_INITVAL_LARGE - TEST_INCREMENT_LARGE)) + +/* Test constants for 8-bit types */ +#define TEST_INITVAL_SMALL 100 +#define TEST_INCREMENT_SMALL 50 +#define TEST_RETVAL_SMALL ((void *)150) +#define TEST_SUBVAL_SMALL ((void *)50) + +/* Test constants for bool (1-bit) */ +#define TEST_INITVAL_BOOL 1 +#define TEST_INCREMENT_BOOL 99 +#define TEST_RETVAL_BOOL ((void *)100) + +/* Buffer size for pointer tests */ +#define TEST_BUFFER_SIZE (TEST_INCREMENT_LARGE + TEST_INCREMENT_SMALL + 256) + +/* Test all C11 standard integer types */ +static int +test_ptr_add_sub_integer_types(void) +{ + unsigned long long ull = TEST_INITVAL_LARGE; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(ull, TEST_INCREMENT_LARGE), TEST_RETVAL_LARGE, + "RTE_PTR_ADD failed for unsigned long long"); + TEST_ASSERT_EQUAL(RTE_PTR_SUB(ull, TEST_INCREMENT_LARGE), TEST_SUBVAL_LARGE, + "RTE_PTR_SUB failed for unsigned long long"); + + long long ll = TEST_INITVAL_LARGE; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(ll, TEST_INCREMENT_LARGE), TEST_RETVAL_LARGE, + "RTE_PTR_ADD failed for long long"); + + unsigned long ul = TEST_INITVAL_LARGE; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(ul, TEST_INCREMENT_LARGE), TEST_RETVAL_LARGE, + "RTE_PTR_ADD failed for unsigned long"); + + long l = TEST_INITVAL_LARGE; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(l, TEST_INCREMENT_LARGE), TEST_RETVAL_LARGE, + "RTE_PTR_ADD failed for long"); + + unsigned int ui = TEST_INITVAL_LARGE; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(ui, TEST_INCREMENT_LARGE), TEST_RETVAL_LARGE, + "RTE_PTR_ADD failed for unsigned int"); + + int i = TEST_INITVAL_LARGE; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(i, TEST_INCREMENT_LARGE), TEST_RETVAL_LARGE, + "RTE_PTR_ADD failed for int"); + + unsigned short us = TEST_INITVAL_LARGE; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(us, TEST_INCREMENT_LARGE), TEST_RETVAL_LARGE, + "RTE_PTR_ADD failed for unsigned short"); + + short s = TEST_INITVAL_LARGE; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(s, TEST_INCREMENT_LARGE), TEST_RETVAL_LARGE, + "RTE_PTR_ADD failed for short"); + + unsigned char uc = TEST_INITVAL_SMALL; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(uc, TEST_INCREMENT_SMALL), TEST_RETVAL_SMALL, + "RTE_PTR_ADD failed for unsigned char"); + + signed char sc = TEST_INITVAL_SMALL; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(sc, TEST_INCREMENT_SMALL), TEST_RETVAL_SMALL, + "RTE_PTR_ADD failed for signed char"); + + char c = TEST_INITVAL_SMALL; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(c, TEST_INCREMENT_SMALL), TEST_RETVAL_SMALL, + "RTE_PTR_ADD failed for char"); + + _Bool b = TEST_INITVAL_BOOL; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(b, TEST_INCREMENT_BOOL), TEST_RETVAL_BOOL, + "RTE_PTR_ADD failed for _Bool"); + + bool b2 = TEST_INITVAL_BOOL; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(b2, TEST_INCREMENT_BOOL), TEST_RETVAL_BOOL, + "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[TEST_BUFFER_SIZE]; + void *result; + + /* Test void* and const void* */ + void *vp = buffer; + result = RTE_PTR_ADD(vp, TEST_INCREMENT_LARGE); + result = RTE_PTR_SUB(result, TEST_INCREMENT_LARGE); + TEST_ASSERT_EQUAL(result, vp, "RTE_PTR_ADD/SUB failed for void*"); + + const void *cvp = buffer; + result = RTE_PTR_ADD(cvp, TEST_INCREMENT_SMALL); + result = RTE_PTR_SUB(result, TEST_INCREMENT_SMALL); + TEST_ASSERT_EQUAL(result, (const void *)cvp, + "RTE_PTR_ADD/SUB failed for const void*"); + + /* Test char* and const char* */ + char *cp = buffer; + result = RTE_PTR_ADD(cp, TEST_INCREMENT_LARGE); + result = RTE_PTR_SUB(result, TEST_INCREMENT_LARGE); + TEST_ASSERT_EQUAL(result, (void *)cp, "RTE_PTR_ADD/SUB failed for char*"); + + const char *ccp = buffer; + result = RTE_PTR_ADD(ccp, TEST_INCREMENT_SMALL); + result = RTE_PTR_SUB(result, TEST_INCREMENT_SMALL); + TEST_ASSERT_EQUAL(result, (const void *)ccp, + "RTE_PTR_ADD/SUB failed for const char*"); + + /* Test uint32_t* and const uint32_t* */ + uint32_t *u32p = (uint32_t *)buffer; + result = RTE_PTR_ADD(u32p, TEST_INCREMENT_LARGE); + result = RTE_PTR_SUB(result, TEST_INCREMENT_LARGE); + TEST_ASSERT_EQUAL(result, (void *)u32p, + "RTE_PTR_ADD/SUB failed for uint32_t*"); + + const uint32_t *cu32p = (const uint32_t *)buffer; + result = RTE_PTR_ADD(cu32p, TEST_INCREMENT_SMALL); + result = RTE_PTR_SUB(result, TEST_INCREMENT_SMALL); + TEST_ASSERT_EQUAL(result, (const void *)cu32p, + "RTE_PTR_ADD/SUB failed for const uint32_t*"); + + /* Verify assigning to const pointer works (adding const is safe) */ + const void *result_const = RTE_PTR_ADD(cvp, TEST_INCREMENT_LARGE); + result_const = RTE_PTR_SUB(result_const, TEST_INCREMENT_LARGE); + TEST_ASSERT_EQUAL(result_const, cvp, + "RTE_PTR_ADD/SUB 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 = TEST_INITVAL_LARGE; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(u64, TEST_INCREMENT_LARGE), TEST_RETVAL_LARGE, + "RTE_PTR_ADD failed for uint64_t"); + + uint32_t u32 = TEST_INITVAL_LARGE; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(u32, TEST_INCREMENT_LARGE), TEST_RETVAL_LARGE, + "RTE_PTR_ADD failed for uint32_t"); + + uint16_t u16 = TEST_INITVAL_LARGE; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(u16, TEST_INCREMENT_LARGE), TEST_RETVAL_LARGE, + "RTE_PTR_ADD failed for uint16_t"); + + uint8_t u8 = TEST_INITVAL_SMALL; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(u8, TEST_INCREMENT_SMALL), TEST_RETVAL_SMALL, + "RTE_PTR_ADD failed for uint8_t"); + + uintptr_t uptr = TEST_INITVAL_LARGE; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(uptr, TEST_INCREMENT_LARGE), TEST_RETVAL_LARGE, + "RTE_PTR_ADD failed for uintptr_t"); + + size_t sz = TEST_INITVAL_LARGE; + TEST_ASSERT_EQUAL(RTE_PTR_ADD(sz, TEST_INCREMENT_LARGE), TEST_RETVAL_LARGE, + "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..b525110b06 100644 --- a/lib/eal/include/rte_common.h +++ b/lib/eal/include/rte_common.h @@ -549,14 +549,20 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void) /*********** Macros for pointer arithmetic ********/ /** - * add a byte-value offset to a pointer + * add and subtract a byte-value offset from a pointer */ -#define RTE_PTR_ADD(ptr, x) ((void*)((uintptr_t)(ptr) + (x))) - +#ifdef RTE_CC_CLANG /** - * subtract a byte-value offset from a pointer + * Clang doesn't optimize through uintptr_t, (char*) enables + * optimizations and doesn't generate warnings. GCC does optimize + * through uintptr_t but throws warnings (e.g. array-bounds) when cast to char*. */ +#define RTE_PTR_ADD(ptr, x) ((void *)((char *)(uintptr_t)(ptr) + (x))) +#define RTE_PTR_SUB(ptr, x) ((void *)((char *)(uintptr_t)(ptr) - (x))) +#else +#define RTE_PTR_ADD(ptr, x) ((void *)((uintptr_t)(ptr) + (x))) #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)