From 59f41af980f95cbd556a6dc2e064b412abc439cf Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Wed, 4 Nov 2015 11:20:04 +0000 Subject: [PATCH] perf llvm: Pass number of configured CPUs to clang compiler This patch introduces a new macro "__NR_CPUS__" to perf's embedded clang compiler, which represent the number of configured CPUs in this system. BPF programs can use this macro to create a map with the same number of system CPUs. For example: struct bpf_map_def SEC("maps") pmu_map = { .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY, .key_size = sizeof(int), .value_size = sizeof(u32), .max_entries = __NR_CPUS__, }; Signed-off-by: Wang Nan Cc: Alexei Starovoitov Cc: Namhyung Kim Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1446636007-239722-2-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/llvm-utils.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/tools/perf/util/llvm-utils.c b/tools/perf/util/llvm-utils.c index 4f6a4780bd5f..80eecefc604f 100644 --- a/tools/perf/util/llvm-utils.c +++ b/tools/perf/util/llvm-utils.c @@ -11,10 +11,11 @@ #include "cache.h" #define CLANG_BPF_CMD_DEFAULT_TEMPLATE \ - "$CLANG_EXEC -D__KERNEL__ $CLANG_OPTIONS " \ - "$KERNEL_INC_OPTIONS -Wno-unused-value " \ - "-Wno-pointer-sign -working-directory " \ - "$WORKING_DIR -c \"$CLANG_SOURCE\" -target bpf -O2 -o -" + "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\ + "$CLANG_OPTIONS $KERNEL_INC_OPTIONS " \ + "-Wno-unused-value -Wno-pointer-sign " \ + "-working-directory $WORKING_DIR " \ + "-c \"$CLANG_SOURCE\" -target bpf -O2 -o -" struct llvm_param llvm_param = { .clang_path = "clang", @@ -326,8 +327,8 @@ get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts) int llvm__compile_bpf(const char *path, void **p_obj_buf, size_t *p_obj_buf_sz) { - int err; - char clang_path[PATH_MAX]; + int err, nr_cpus_avail; + char clang_path[PATH_MAX], nr_cpus_avail_str[64]; const char *clang_opt = llvm_param.clang_opt; const char *template = llvm_param.clang_bpf_cmd_template; char *kbuild_dir = NULL, *kbuild_include_opts = NULL; @@ -354,6 +355,17 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf, */ get_kbuild_opts(&kbuild_dir, &kbuild_include_opts); + nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF); + if (nr_cpus_avail <= 0) { + pr_err( +"WARNING:\tunable to get available CPUs in this system: %s\n" +" \tUse 128 instead.\n", strerror(errno)); + nr_cpus_avail = 128; + } + snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d", + nr_cpus_avail); + + force_set_env("NR_CPUS", nr_cpus_avail_str); force_set_env("CLANG_EXEC", clang_path); force_set_env("CLANG_OPTIONS", clang_opt); force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts); -- 2.20.1