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([2602:ae:1598:4c01:17a4:1aa0:c49d:e8f7]) by smtp.gmail.com with ESMTPSA id t9-20020a170902e84900b001ab1d23bf5dsm225592plg.258.2023.05.17.21.41.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 May 2023 21:41:04 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Cc: peter.maydell@linaro.org Subject: [PATCH 5/9] util/bufferiszero: Use i386 cpuinfo.h Date: Wed, 17 May 2023 21:40:54 -0700 Message-Id: <20230518044058.2777467-6-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230518044058.2777467-1-richard.henderson@linaro.org> References: <20230518044058.2777467-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2607:f8b0:4864:20::42c; envelope-from=richard.henderson@linaro.org; helo=mail-pf1-x42c.google.com X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, DKIM_INVALID=0.1, DKIM_SIGNED=0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Use cpuinfo_init() during init_accel(), and the variable cpuinfo during test_buffer_is_zero_next_accel(). Adjust the logic that cycles through the set of accelerators for testing. Signed-off-by: Richard Henderson --- util/bufferiszero.c | 126 ++++++++++++++++---------------------------- 1 file changed, 45 insertions(+), 81 deletions(-) diff --git a/util/bufferiszero.c b/util/bufferiszero.c index 1886bc5ba4..f216d07b76 100644 --- a/util/bufferiszero.c +++ b/util/bufferiszero.c @@ -24,6 +24,7 @@ #include "qemu/osdep.h" #include "qemu/cutils.h" #include "qemu/bswap.h" +#include "cpuinfo.h" static bool buffer_zero_int(const void *buf, size_t len) @@ -184,111 +185,74 @@ buffer_zero_avx512(const void *buf, size_t len) } #endif /* CONFIG_AVX512F_OPT */ - -/* Note that for test_buffer_is_zero_next_accel, the most preferred - * ISA must have the least significant bit. - */ -#define CACHE_AVX512F 1 -#define CACHE_AVX2 2 -#define CACHE_SSE4 4 -#define CACHE_SSE2 8 - -/* Make sure that these variables are appropriately initialized when +/* + * Make sure that these variables are appropriately initialized when * SSE2 is enabled on the compiler command-line, but the compiler is * too old to support CONFIG_AVX2_OPT. */ #if defined(CONFIG_AVX512F_OPT) || defined(CONFIG_AVX2_OPT) -# define INIT_CACHE 0 -# define INIT_ACCEL buffer_zero_int +# define INIT_USED 0 +# define INIT_LENGTH 0 +# define INIT_ACCEL buffer_zero_int #else # ifndef __SSE2__ # error "ISA selection confusion" # endif -# define INIT_CACHE CACHE_SSE2 -# define INIT_ACCEL buffer_zero_sse2 +# define INIT_USED CPUINFO_SSE2 +# define INIT_LENGTH 64 +# define INIT_ACCEL buffer_zero_sse2 #endif -static unsigned cpuid_cache = INIT_CACHE; +static unsigned used_accel = INIT_USED; +static unsigned length_to_accel = INIT_LENGTH; static bool (*buffer_accel)(const void *, size_t) = INIT_ACCEL; -static int length_to_accel = 64; -static void init_accel(unsigned cache) +static unsigned __attribute__((noinline)) +select_accel_cpuinfo(unsigned info) { - bool (*fn)(const void *, size_t) = buffer_zero_int; - if (cache & CACHE_SSE2) { - fn = buffer_zero_sse2; - length_to_accel = 64; - } -#ifdef CONFIG_AVX2_OPT - if (cache & CACHE_SSE4) { - fn = buffer_zero_sse4; - length_to_accel = 64; - } - if (cache & CACHE_AVX2) { - fn = buffer_zero_avx2; - length_to_accel = 128; - } -#endif + static const struct { + unsigned bit; + unsigned len; + bool (*fn)(const void *, size_t); + } all[] = { #ifdef CONFIG_AVX512F_OPT - if (cache & CACHE_AVX512F) { - fn = buffer_zero_avx512; - length_to_accel = 256; - } + { CPUINFO_AVX512F, 256, buffer_zero_avx512 }, #endif - buffer_accel = fn; +#ifdef CONFIG_AVX2_OPT + { CPUINFO_AVX2, 128, buffer_zero_avx2 }, + { CPUINFO_SSE4, 64, buffer_zero_sse4 }, +#endif + { CPUINFO_SSE2, 64, buffer_zero_sse2 }, + { CPUINFO_ALWAYS, 0, buffer_zero_int }, + }; + + for (unsigned i = 0; i < ARRAY_SIZE(all); ++i) { + if (info & all[i].bit) { + length_to_accel = all[i].len; + buffer_accel = all[i].fn; + return all[i].bit; + } + } + return 0; } #if defined(CONFIG_AVX512F_OPT) || defined(CONFIG_AVX2_OPT) -#include "qemu/cpuid.h" - -static void __attribute__((constructor)) init_cpuid_cache(void) +static void __attribute__((constructor)) init_accel(void) { - unsigned max = __get_cpuid_max(0, NULL); - int a, b, c, d; - unsigned cache = 0; - - if (max >= 1) { - __cpuid(1, a, b, c, d); - if (d & bit_SSE2) { - cache |= CACHE_SSE2; - } - if (c & bit_SSE4_1) { - cache |= CACHE_SSE4; - } - - /* We must check that AVX is not just available, but usable. */ - if ((c & bit_OSXSAVE) && (c & bit_AVX) && max >= 7) { - unsigned bv = xgetbv_low(0); - __cpuid_count(7, 0, a, b, c, d); - if ((bv & 0x6) == 0x6 && (b & bit_AVX2)) { - cache |= CACHE_AVX2; - } - /* 0xe6: - * XCR0[7:5] = 111b (OPMASK state, upper 256-bit of ZMM0-ZMM15 - * and ZMM16-ZMM31 state are enabled by OS) - * XCR0[2:1] = 11b (XMM state and YMM state are enabled by OS) - */ - if ((bv & 0xe6) == 0xe6 && (b & bit_AVX512F)) { - cache |= CACHE_AVX512F; - } - } - } - cpuid_cache = cache; - init_accel(cache); + used_accel = select_accel_cpuinfo(cpuinfo_init()); } #endif /* CONFIG_AVX2_OPT */ bool test_buffer_is_zero_next_accel(void) { - /* If no bits set, we just tested buffer_zero_int, and there - are no more acceleration options to test. */ - if (cpuid_cache == 0) { - return false; - } - /* Disable the accelerator we used before and select a new one. */ - cpuid_cache &= cpuid_cache - 1; - init_accel(cpuid_cache); - return true; + /* + * Accumulate the accelerators that we've already tested, and + * remove them from the set to test this round. We'll get back + * a zero from select_accel_cpuinfo when there are no more. + */ + unsigned used = select_accel_cpuinfo(cpuinfo & ~used_accel); + used_accel |= used; + return used; } static bool select_accel_fn(const void *buf, size_t len) -- 2.34.1