Bug 102252

Need to create a new section for OA bugs. Will try to discuss that with the main dev.

I have this series to help out with the flakyness of this test :
https://patchwork.freedesktop.org/series/28373/

Not landed yet, hopefully soon!

This is also visible on the following test: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_2970/shard-hsw3/igt@perf@polling.html

Tested-by - the series 28373 seem to improve the situation on my dev-skl-i5-6600k having 

Without series (IGT-Version: 1.19-g5ce65a9a):
Subtest oa-exponents: FAIL (0,214s)
Subtest per-context-mode-unprivileged: FAIL (0,004s)
Subtest polling: FAIL (10,032s)
Subtest short-reads: FAIL (0,001s)
Subtest mi-rpc: FAIL (0,001s)
Subtest rc6-disable: FAIL (0,001s)
Subtest create-destroy-userspace-config: FAIL (0,003s)

With series 28373 applied on above:
Subtest i915-ref-count: SUCCESS (0,043s)
Subtest sysctl-defaults: SUCCESS (0,000s)
Subtest non-system-wide-paranoid: SUCCESS (0,015s)
Subtest invalid-open-flags: SUCCESS (0,000s)
Subtest invalid-oa-metric-set-id: SUCCESS (0,007s)
Subtest invalid-oa-format-id: SUCCESS (0,008s)
Subtest missing-sample-flags: SUCCESS (0,000s)
Subtest oa-formats: SUCCESS (0,073s)
Subtest invalid-oa-exponent: SUCCESS (0,007s)
Subtest low-oa-exponent-permissions: SUCCESS (0,015s)
Subtest oa-exponents: SUCCESS (15,035s)
Test requirement not met in function __real_main4515, file perf.c:4580:
Test requirement: IS_HASWELL(devid)
Subtest per-context-mode-unprivileged: SKIP (0,000s)
Subtest buffer-fill: SUCCESS (1,734s)
Subtest disabled-read-error: SUCCESS (0,037s)
Subtest non-sampling-read-error: SUCCESS (0,007s)
Subtest enable-disable: SUCCESS (1,730s)
Subtest blocking: SUCCESS (10,022s)
Subtest polling: SUCCESS (10,010s)
Subtest short-reads: SUCCESS (0,020s)
Subtest mi-rpc: SUCCESS (0,009s)
Test requirement not met in function __real_main4515, file perf.c:4608:
Test requirement: IS_HASWELL(devid)
Subtest unprivileged-single-ctx-counters: SKIP (0,000s)
Subtest gen8-unprivileged-single-ctx-counters: SUCCESS (0,027s)
Subtest rc6-disable: SUCCESS (1,510s)
Subtest invalid-create-userspace-config: SUCCESS (0,000s)
Subtest invalid-remove-userspace-config: SUCCESS (0,007s)
Subtest create-destroy-userspace-config: SUCCESS (0,022s)
Subtest whitelisted-registers-userspace-config: SUCCESS (0,000s)

For HSW, APL, KBL see shards results https://intel-gfx-ci.01.org/tree/drm-tip/IGTPW_132/shards.html
E.g. HSW has Test perf:
        Subgroup polling:
                fail       -> PASS       (shard-hsw) fdo#102252
        Subgroup oa-exponents:
                fail       -> PASS       (shard-hsw) fdo#102254

Changing component to IGT since fault is in intel-gpu-tools git.

Just pushed a series that should make this failure go away.
Feel free to reopen if needed.
The 2 commits related to this issue :

https://cgit.freedesktop.org/drm/igt-gpu-tools/commit/?id=eafaf4fb49ba7a02c11def787b5de2a14de532f2

https://cgit.freedesktop.org/drm/igt-gpu-tools/commit/?id=f1514a6320f65a1524f36407f7f22d6fc7c7679e

The issue is not reproduced from:
https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_3175

Unfortunately this has been reproduced:
https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_3183/shard-hsw6/igt@perf@polling.html

I think perf/OA on hsw has some hw limitations that we try to work around, but fundamentally it's not possible. So even with best effort, everyone once in a while this will go wrong.

Note: This _only_ applies to hsw. I think later platforms should work better.

Not sure what's wrong with HSW. It seems to be just off by 1, so it could be that the test doesn't account for an edge case scenario.
Unfortunately I haven't had time to investigate HSW so far :(

I bow to jani nikkula and set this bug to closed/wontfix