On the HiSilicon platform, there is one ETM per logic core. When setting up SMT, not every process has an ETM. So the path ".../cs_etm/cpux/trcidr/trcidr0" does not exist, the function perf_pmu__scan_file() return an error. However, the command 'perf record' will returns silently and don't print.
After this patch, log a error when read fails that makes it easy for users to debug.
root@localhost:/# perf record -e /cs_etm/@ultra_smb0/ -C 3 uname -a cs_etm: can't read file cpu3/trcidr/trcidr0 root@localhost:/#
Signed-off-by: Junhao He hejunhao3@huawei.com --- tools/perf/arch/arm/util/cs-etm.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c index 7f71c8a237ff..19ea17430399 100644 --- a/tools/perf/arch/arm/util/cs-etm.c +++ b/tools/perf/arch/arm/util/cs-etm.c @@ -585,7 +585,6 @@ cs_etm_info_priv_size(struct auxtrace_record *itr __maybe_unused,
static bool cs_etm_is_etmv4(struct auxtrace_record *itr, int cpu) { - bool ret = false; char path[PATH_MAX]; int scan; unsigned int val; @@ -600,9 +599,10 @@ static bool cs_etm_is_etmv4(struct auxtrace_record *itr, int cpu)
/* The file was read successfully, we have a winner */ if (scan == 1) - ret = true; + return true;
- return ret; + pr_err("%s: can't read file %s\n", CORESIGHT_ETM_PMU_NAME, path); + return false; }
static int cs_etm_get_ro(struct perf_pmu *pmu, int cpu, const char *path)