Commit-ID: 59f41af980f95cbd556a6dc2e064b412abc439cf
Gitweb: http://git.kernel.org/tip/59f41af980f95cbd556a6dc2e064b412abc439cf
Author: Wang Nan <wangnan0@xxxxxxxxxx>
AuthorDate: Wed, 4 Nov 2015 11:20:04 +0000
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Thu, 5 Nov 2015 12:47:02 -0300
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 <wangnan0@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
Link: http://lkml.kernel.org/r/1446636007-239722-2-git-send-email-wangnan0@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
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 4f6a478..80eecef 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);
--
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