Re: [PATCH 2/4] tests/intel/xe_oa: Do not assume OA buffer is prefilled with zeroes

On Mon, Jul 20, 2026 at 12:42:44PM -0700, Dixit, Ashutosh wrote:
>On Fri, 17 Jul 2026 14:00:30 -0700, Umesh Nerlige Ramappa wrote:
>>
>> The tail address test assumes that the OA buffer is preset to zeroes. Modify
>> logic to be independent of this assumption.
>
>Are we going to stop memset'ing OA buffer to 0 in the kernel? Even

Yes, I am planning to remove the memset in the kernel.

>otherwise, because this patch is a generalization of the OA buffer being 0:
>
>Reviewed-by: Ashutosh Dixit <[email protected]>

Thanks,
Umesh
>
>
>>
>> Signed-off-by: Umesh Nerlige Ramappa <[email protected]>
>> ---
>>  tests/intel/xe_oa.c | 29 ++++++++++++++++++-----------
>>  1 file changed, 18 insertions(+), 11 deletions(-)
>>
>> diff --git a/tests/intel/xe_oa.c b/tests/intel/xe_oa.c
>> index e7e4f5601b61..98f00d377a86 100644
>> --- a/tests/intel/xe_oa.c
>> +++ b/tests/intel/xe_oa.c
>> @@ -4634,7 +4634,7 @@ static void closed_fd_and_unmapped_access(const struct drm_xe_oa_unit *oau)
>>   * format size is not a power of 2. This means that the last report will not be
>>   * broken down across the OA buffer end. Instead it will be written to the
>>   * beginning of the OA buffer. We will check the end of the buffer to ensure it
>> - * has zeroes in it.
>> + * has not been written into.
>>   */
>>  static void
>>  test_tail_address_wrap(const struct drm_xe_oa_unit *oau, size_t oa_buffer_size)
>> @@ -4649,6 +4649,7 @@ test_tail_address_wrap(const struct drm_xe_oa_unit *oau, size_t oa_buffer_size)
>>		DRM_XE_OA_PROPERTY_OA_METRIC_SET, test_set->perf_oa_metrics_set,
>>		DRM_XE_OA_PROPERTY_OA_FORMAT, __ff(fmt),
>>		DRM_XE_OA_PROPERTY_OA_PERIOD_EXPONENT, exponent,
>> +		DRM_XE_OA_PROPERTY_OA_DISABLED, true,
>>		DRM_XE_OA_PROPERTY_OA_BUFFER_SIZE, buffer_size,
>>	};
>>	struct intel_xe_oa_open_prop param = {
>> @@ -4656,25 +4657,31 @@ test_tail_address_wrap(const struct drm_xe_oa_unit *oau, size_t oa_buffer_size)
>>		.properties_ptr = to_user_pointer(properties),
>>	};
>>	u32 fmt_size = get_oa_format(fmt).size;
>> -	u32 zero_size = buffer_size % fmt_size;
>> -	u32 *zero_area, *buffer_end, *buffer_start;
>> +	u32 area_size = buffer_size % fmt_size;
>> +	u32 *area, *buffer_end, *buffer_start;
>> +	u32 *content = malloc(area_size);
>>
>> -	igt_require(zero_size);
>> +	igt_require(area_size);
>> +	igt_require(content);
>
>igt_assert(content);
>
>>
>>	stream_fd = __perf_open(drm_fd, &param, false);
>>	set_fd_flags(stream_fd, O_CLOEXEC);
>> -
>> -	wait_for_oa_buffer_overflow(stream_fd, 100);
>> -
>>	buffer_start = mmap(0, buffer_size, PROT_READ, MAP_PRIVATE, stream_fd, 0);
>>	igt_assert(buffer_start);
>>
>> -	zero_area = buffer_start + (buffer_size - zero_size) / 4;
>> +	area = buffer_start + (buffer_size - area_size) / 4;
>>	buffer_end = buffer_start + buffer_size / 4;
>>
>> -	dump_report(zero_area, zero_size / 4, "zero_area");
>> -	while (zero_area < buffer_end)
>> -		igt_assert_eq(*zero_area++, 0);
>> +	memcpy(content, area, area_size);
>> +	dump_report(area, area_size / 4, "contents before");
>> +
>> +	do_ioctl(stream_fd, DRM_XE_OBSERVATION_IOCTL_ENABLE, 0);
>> +	wait_for_oa_buffer_overflow(stream_fd, 100);
>> +	do_ioctl(stream_fd, DRM_XE_OBSERVATION_IOCTL_DISABLE, 0);
>> +
>> +	dump_report(area, area_size / 4, "contents after");
>> +	while (area < buffer_end)
>> +		igt_assert_eq(*area++, *content++);
>>
>>	munmap(buffer_start, buffer_size);
>>
>> --
>> 2.51.0
>>