Re: [PATCH V4 1/2] tools/perf: Fix the check for parameterized field in event term

On Mon, May 04, 2026 at 09:12:04PM +0530, Athira Rajeev wrote:

The format_alias() function in util/pmu.c has a check to
detect whether the event has parameterized field ( =? ).
The string alias->terms contains the event and if the event
has user configurable parameter, there will be presence of
sub string "=?" in the alias->terms.

Snippet of code:

 /* Paramemterized events have the parameters shown. */
       if (strstr(alias->terms, "=?")) {
               /* No parameters. */
               snprintf(buf, len, "%.*s/%s/", (int)pmu_name_len, pmu->name, alias->name);

if "strstr" contains the substring, it returns a pointer
and hence enters the above check which is not the expected
check. And hence "perf list" doesn't have the parameterized
fields in the result.

Fix this check to use:

if (!strstr(alias->terms, "=?")) {

With this change, perf list shows the events correctly with
the strings showing parameters.

Before the fix:

 # ./perf list|grep -w PM_PAU_CYC
  hv_24x7/PM_PAU_CYC/                                [Kernel PMU event]

With this fix:

 # ./perf list|grep -w PM_PAU_CYC
  hv_24x7/PM_PAU_CYC,chip=?/                         [Kernel PMU event]

Signed-off-by: Athira Rajeev <redacted>

Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung