[igt-dev] [PATCH i-g-t] i915/perf: Make sure i915 is loaded before reading proc

[Umesh Nerlige Ramappa]

On Fri, Oct 30, 2020 at 12:16:03PM +0200, Petri Latvala wrote:
>On Thu, Oct 29, 2020 at 05:39:11PM -0700, Umesh Nerlige Ramappa wrote:
>> The previous test may have unloaded i915 or failed to load it back. To
>> combat such cases, each test fixture is supposed to ensure that i915 is
>> loaded prior to running the subtests. In most fixtures this happens
>> automatically when we try to get a handle to i915. In perf OA, we stat
>> some proc/sys files even before getting a handle to i915. Occassionally,
>> perf tests fail trying to stat these files. Fix perf OA by checking and
>> loading i915 if it's not loaded.
>>
>> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/405
>> Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
>> ---
>
>I had a patch also fixing this back in August but I guess I didn't CC
>the correct people (in fact CCd none).
>
>https://patchwork.freedesktop.org/series/80805/
>
>Same comment as for that other patch by Chris, we might want to
>generalize this by exporting __try_modprobe to be callable from tests.

Thanks Petri,

Ashutosh suggested that there is no need to check igt_kmod_is_loaded.  
That happens within igt_i915_driver_load. I will remove the if and post 
v2.

Thanks,
Umesh

>
>Anyway,
>Reviewed-by: Petri Latvala <petri.latvala at intel.com>
>
>
>
>
>>  tests/i915/perf.c | 9 +++++++++
>>  1 file changed, 9 insertions(+)
>>
>> diff --git a/tests/i915/perf.c b/tests/i915/perf.c
>> index a5c4adc3..a5bd63c2 100644
>> --- a/tests/i915/perf.c
>> +++ b/tests/i915/perf.c
>> @@ -41,6 +41,7 @@
>>  #include "i915/gem.h"
>>  #include "i915/perf.h"
>>  #include "igt.h"
>> +#include "igt_kmod.h"
>>  #include "igt_sysfs.h"
>>  #include "drm.h"
>>
>> @@ -4806,6 +4807,14 @@ igt_main
>>  	igt_fixture {
>>  		struct stat sb;
>>
>> +               /*
>> +		* Prior tests may have unloaded i915 or failed while
>> +		* loading/unloading i915. Load i915 here before we stat the
>> +		* files.
>> +                */
>> +               if (!igt_kmod_is_loaded("i915"))
>> +                       igt_assert(!igt_i915_driver_load(NULL));
>> +
>>  		igt_require(stat("/proc/sys/dev/i915/perf_stream_paranoid", &sb)
>>  			    == 0);
>>  		igt_require(stat("/proc/sys/dev/i915/oa_max_sample_rate", &sb)
>> --
>> 2.20.1
>>
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