@@ -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);
This patch introduces a new macro "__NR_CPUS__" to perf's embedded clang compiler, which represent the available CPU counters in this system. BPF program can use this macro to create a map with same number of system CPUs. For exmaple: 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 <wangnan0@huawei.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Ahern <dsahern@gmail.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kaixu Xia <xiakaixu@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/n/ebpf-y603iy62s8w4br4t2gxfois4@git.kernel.org --- tools/perf/util/llvm-utils.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-)