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Reviewed-by: Zide Chen Signed-off-by: Chun-Tse Shao Assisted-by: Gemini:gemini-3.1-pro-preview --- v7: Fixed based on Sashiko review: - Refactor PMU initialization to be fully thread-safe using pthread_once and pthread_mutex locks. - Fix a critical bounds check bug on single-socket systems. - Fix potential divide-by-zero crash in uncore_cha_snc. - Avoid spurious warnings on non-SNC systems. - Avoid silent and inconsistent uncore mappings on unsupported SNC configurations. - Resolve checkpatch linter warnings. v6: lore.kernel.org/20260515172710.428474-1-ctshao@google.com Make string literal. Add SPR into SNC2. v5: lore.kernel.org/20260407203918.3178481-1-ctshao@google.com Split patch. v4: lore.kernel.org/20260402205300.1953706-1-ctshao@google.com Rebase. v3: lore.kernel.org/20260212223942.3832857-1-ctshao@google.com Fix a typo. v2: lore.kernel.org/20260205232220.1980168-1-ctshao@google.com Split EMR and GNR in the SNC2 IMC cpu map. v1: lore.kernel.org/20260108184430.1210223-1-ctshao@google.com tools/perf/arch/x86/util/pmu.c | 199 +++++++++++++++++++++------------ 1 file changed, 130 insertions(+), 69 deletions(-) diff --git a/tools/perf/arch/x86/util/pmu.c b/tools/perf/arch/x86/util/pmu.c index 7c9d238922a6..9b00d5720fb7 100644 --- a/tools/perf/arch/x86/util/pmu.c +++ b/tools/perf/arch/x86/util/pmu.c @@ -1,4 +1,5 @@ // SPDX-License-Identifier: GPL-2.0 +#include #include #include #include @@ -22,20 +23,31 @@ #include "util/env.h" #include "util/header.h" -static bool x86__is_intel_graniterapids(void) -{ - static bool checked_if_graniterapids; - static bool is_graniterapids; +#define GENUINE_INTEL_GNR "GenuineIntel-6-A[DE]" - if (!checked_if_graniterapids) { - const char *graniterapids_cpuid = "GenuineIntel-6-A[DE]"; - char *cpuid = get_cpuid_str((struct perf_cpu){0}); +static bool cached_snc_supported; +static pthread_once_t snc_support_once = PTHREAD_ONCE_INIT; - is_graniterapids = cpuid && strcmp_cpuid_str(graniterapids_cpuid, cpuid) == 0; - free(cpuid); - checked_if_graniterapids = true; +static void init_snc_support(void) +{ + /* Graniterapids supports SNC configuration. */ + static const char *const supported_cpuids[] = { + GENUINE_INTEL_GNR, /* Graniterapids */ + }; + char *cpuid = get_cpuid_str((struct perf_cpu){0}); + + for (size_t i = 0; i < ARRAY_SIZE(supported_cpuids); i++) { + cached_snc_supported = cpuid && strcmp_cpuid_str(supported_cpuids[i], cpuid) == 0; + if (cached_snc_supported) + break; } - return is_graniterapids; + free(cpuid); +} + +static bool x86__is_snc_supported(void) +{ + pthread_once(&snc_support_once, init_snc_support); + return cached_snc_supported; } static struct perf_cpu_map *read_sysfs_cpu_map(const char *sysfs_path) @@ -52,49 +64,58 @@ static struct perf_cpu_map *read_sysfs_cpu_map(const char *sysfs_path) return cpus; } -static int snc_nodes_per_l3_cache(void) +static int cached_snc_nodes; +static pthread_once_t snc_nodes_once = PTHREAD_ONCE_INIT; + +static void init_snc_nodes(void) { - static bool checked_snc; - static int snc_nodes; - - if (!checked_snc) { - struct perf_cpu_map *node_cpus = - read_sysfs_cpu_map("devices/system/node/node0/cpulist"); - struct perf_cpu_map *cache_cpus = - read_sysfs_cpu_map("devices/system/cpu/cpu0/cache/index3/shared_cpu_list"); - - snc_nodes = perf_cpu_map__nr(cache_cpus) / perf_cpu_map__nr(node_cpus); - perf_cpu_map__put(cache_cpus); - perf_cpu_map__put(node_cpus); - checked_snc = true; - } - return snc_nodes; + struct perf_cpu_map *node_cpus = + read_sysfs_cpu_map("devices/system/node/node0/cpulist"); + struct perf_cpu_map *cache_cpus = + read_sysfs_cpu_map("devices/system/cpu/cpu0/cache/index3/shared_cpu_list"); + + if (node_cpus && cache_cpus) + cached_snc_nodes = perf_cpu_map__nr(cache_cpus) / perf_cpu_map__nr(node_cpus); + else + cached_snc_nodes = 0; + perf_cpu_map__put(cache_cpus); + perf_cpu_map__put(node_cpus); } -static int num_chas(void) +static int snc_nodes_per_l3_cache(void) { - static bool checked_chas; - static int num_chas; + pthread_once(&snc_nodes_once, init_snc_nodes); + return cached_snc_nodes; +} - if (!checked_chas) { - int fd = perf_pmu__event_source_devices_fd(); - struct io_dir dir; - struct io_dirent64 *dent; +static int cached_num_chas; +static pthread_once_t num_chas_once = PTHREAD_ONCE_INIT; - if (fd < 0) - return -1; +static void init_num_chas(void) +{ + int fd = perf_pmu__event_source_devices_fd(); + struct io_dir dir; + struct io_dirent64 *dent; - io_dir__init(&dir, fd); + if (fd < 0) { + cached_num_chas = -1; + return; + } - while ((dent = io_dir__readdir(&dir)) != NULL) { - /* Note, dent->d_type will be DT_LNK and so isn't a useful filter. */ - if (strstarts(dent->d_name, "uncore_cha_")) - num_chas++; - } - close(fd); - checked_chas = true; + io_dir__init(&dir, fd); + + while ((dent = io_dir__readdir(&dir)) != NULL) { + /* Note, dent->d_type will be DT_LNK and so isn't a useful filter. */ + if (strstarts(dent->d_name, "uncore_cha_")) + cached_num_chas++; } - return num_chas; + close(fd); +} + +static int num_chas(void) +{ + pthread_once(&num_chas_once, init_num_chas); + return cached_num_chas; } #define MAX_SNCS 6 @@ -121,46 +142,73 @@ static int uncore_cha_snc(struct perf_pmu *pmu) return 0; } chas_per_node = num_cha / snc_nodes; + if (chas_per_node == 0) { + pr_warning("Unexpected: chas_per_node is 0 (num_cha=%d, snc_nodes=%d)\n", + num_cha, snc_nodes); + return 0; + } cha_snc = cha_num / chas_per_node; /* Range check cha_snc. for unexpected out of bounds. */ return cha_snc >= MAX_SNCS ? 0 : cha_snc; } -static int uncore_imc_snc(struct perf_pmu *pmu) +static const u8 *cached_imc_snc_map; +static size_t cached_imc_snc_map_len; +static pthread_once_t imc_snc_map_once = PTHREAD_ONCE_INIT; + +static void init_snc_map(void) { - // Compute the IMC SNC using lookup tables. - unsigned int imc_num; int snc_nodes = snc_nodes_per_l3_cache(); - const u8 snc2_map[] = {1, 1, 0, 0, 1, 1, 0, 0}; - const u8 snc3_map[] = {1, 1, 0, 0, 2, 2, 1, 1, 0, 0, 2, 2}; - const u8 *snc_map; - size_t snc_map_len; + char *cpuid; + static const u8 gnr_snc2_map[] = { 1, 1, 0, 0 }; + static const u8 snc3_map[] = { 1, 1, 0, 0, 2, 2 }; switch (snc_nodes) { case 2: - snc_map = snc2_map; - snc_map_len = ARRAY_SIZE(snc2_map); + cpuid = get_cpuid_str((struct perf_cpu){ 0 }); + if (cpuid) { + if (strcmp_cpuid_str(GENUINE_INTEL_GNR, cpuid) == 0) { + cached_imc_snc_map = gnr_snc2_map; + cached_imc_snc_map_len = ARRAY_SIZE(gnr_snc2_map); + } + free(cpuid); + } break; case 3: - snc_map = snc3_map; - snc_map_len = ARRAY_SIZE(snc3_map); + cached_imc_snc_map = snc3_map; + cached_imc_snc_map_len = ARRAY_SIZE(snc3_map); break; default: /* Error or no lookup support for SNC with >3 nodes. */ - return 0; + break; } + if (!cached_imc_snc_map) + pr_warning("Unexpected: can not find snc map config\n"); +} + +static int uncore_imc_snc(struct perf_pmu *pmu) +{ + // Compute the IMC SNC using lookup tables. + unsigned int imc_num; + int snc_nodes = snc_nodes_per_l3_cache(); + + if (snc_nodes <= 1) + return 0; + + pthread_once(&imc_snc_map_once, init_snc_map); + /* Compute SNC for PMU. */ if (sscanf(pmu->name, "uncore_imc_%u", &imc_num) != 1) { pr_warning("Unexpected: unable to compute IMC number '%s'\n", pmu->name); return 0; } - if (imc_num >= snc_map_len) { - pr_warning("Unexpected IMC %d for SNC%d mapping\n", imc_num, snc_nodes); + + if (!cached_imc_snc_map) return 0; - } - return snc_map[imc_num]; + + return cached_imc_snc_map[imc_num % cached_imc_snc_map_len]; } static int uncore_cha_imc_compute_cpu_adjust(int pmu_snc) @@ -200,7 +248,9 @@ static int uncore_cha_imc_compute_cpu_adjust(int pmu_snc) return cpu_adjust[pmu_snc]; } -static void gnr_uncore_cha_imc_adjust_cpumask_for_snc(struct perf_pmu *pmu, bool cha) +static pthread_mutex_t pmu_adjust_mutex = PTHREAD_MUTEX_INITIALIZER; + +static void uncore_cha_imc_adjust_cpumask_for_snc(struct perf_pmu *pmu, bool cha) { // With sub-NUMA clustering (SNC) there is a NUMA node per SNC in the // topology. For example, a two socket graniterapids machine may be set @@ -231,9 +281,11 @@ static void gnr_uncore_cha_imc_adjust_cpumask_for_snc(struct perf_pmu *pmu, bool return; } + pthread_mutex_lock(&pmu_adjust_mutex); + pmu_snc = cha ? uncore_cha_snc(pmu) : uncore_imc_snc(pmu); if (pmu_snc == 0) { - // No adjustment necessary for the first SNC. + pthread_mutex_unlock(&pmu_adjust_mutex); return; } @@ -242,8 +294,10 @@ static void gnr_uncore_cha_imc_adjust_cpumask_for_snc(struct perf_pmu *pmu, bool // Hold onto the perf_cpu_map globally to avoid recomputation. cpu_adjust = uncore_cha_imc_compute_cpu_adjust(pmu_snc); adjusted[pmu_snc] = perf_cpu_map__empty_new(perf_cpu_map__nr(pmu->cpus)); - if (!adjusted[pmu_snc]) + if (!adjusted[pmu_snc]) { + pthread_mutex_unlock(&pmu_adjust_mutex); return; + } } perf_cpu_map__for_each_cpu(cpu, idx, pmu->cpus) { @@ -263,6 +317,8 @@ static void gnr_uncore_cha_imc_adjust_cpumask_for_snc(struct perf_pmu *pmu, bool perf_cpu_map__put(pmu->cpus); pmu->cpus = perf_cpu_map__get(adjusted[pmu_snc]); + + pthread_mutex_unlock(&pmu_adjust_mutex); } void perf_pmu__arch_init(struct perf_pmu *pmu) @@ -300,11 +356,16 @@ void perf_pmu__arch_init(struct perf_pmu *pmu) pmu->mem_events = perf_mem_events_intel_aux; else pmu->mem_events = perf_mem_events_intel; - } else if (x86__is_intel_graniterapids()) { - if (strstarts(pmu->name, "uncore_cha_")) - gnr_uncore_cha_imc_adjust_cpumask_for_snc(pmu, /*cha=*/true); - else if (strstarts(pmu->name, "uncore_imc_")) - gnr_uncore_cha_imc_adjust_cpumask_for_snc(pmu, /*cha=*/false); + } else if (x86__is_snc_supported()) { + int snc_nodes = snc_nodes_per_l3_cache(); + + if (snc_nodes == 2 || snc_nodes == 3) { + if (strstarts(pmu->name, "uncore_cha_")) + uncore_cha_imc_adjust_cpumask_for_snc(pmu, /*cha=*/true); + else if (strstarts(pmu->name, "uncore_imc_") && + !strstarts(pmu->name, "uncore_imc_free_running")) + uncore_cha_imc_adjust_cpumask_for_snc(pmu, /*cha=*/false); + } } } } -- 2.54.0.823.g6e5bcc1fc9-goog