Testing the stealing of guc ids is hard from user space as we have 64k
guc_ids. Add a selftest, which artificially reduces the number of guc
ids, and forces a steal.
The test creates a spinner which is used to block all subsequent
submissions until it completes. Next, a loop creates a context and a NOP
request each iteration until the guc_ids are exhausted (request creation
returns -EAGAIN). The spinner is ended, unblocking all requests created
in the loop. At this point all guc_ids are exhausted but are available
to steal. Try to create another request which should successfully steal
a guc_id. Wait on last request to complete, idle GPU, verify a guc_id
was stolen via a counter, and exit the test. Test also artificially
reduces the number of guc_ids so the test runs in a timely manner.
v2:
(John Harrison)
- s/stole/stolen
- Fix some wording in test description
- Rework indexing into context array
- Add test description to commit message
- Fix typo in commit message
(Checkpatch)
- s/guc/(guc) in NUMBER_MULTI_LRC_GUC_ID
v3:
(John Harrison)
- Set array value to NULL after extracting error
- Fix a few typos in comments / error messages
- Delete redundant comment in commit message
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211214170500.28569-8-matthew.brost@intel.com
While debugging an issue with full GT resets I went down a rabbit hole
thinking the scrubbing of lost G2H wasn't working correctly. This proved
to be incorrect as this was working just fine but this chase inspired me
to write a selftest to prove that this works. This simple selftest
injects errors dropping various G2H and then issues a full GT reset
proving that the scrubbing of these G2H doesn't blow up.
v2:
(Daniel Vetter)
- Use ifdef instead of macros for selftests
v3:
(Checkpatch)
- A space after 'switch' statement
v4:
(Daniele)
- A comment saying GT won't idle if G2H are lost
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210909164744.31249-12-matthew.brost@intel.com
Instead of relying on the workqueue, the upcoming reworked GuC
submission flow will offer the host driver indipendent control over
the execution status of each context submitted to GuC. As part of this,
the doorbell usage model has been reworked, with each doorbell being
paired to a single lrc and a doorbell ring representing new work
available for that specific context. This mechanism, however, limits
the number of contexts that can be registered with GuC to the number of
doorbells, which is an undesired limitation. To avoid this limitation,
we requested the GuC team to also provide a H2G that will allow the host
to notify the GuC of work available for a specified lrc, so we can use
that mechanism instead of relying on the doorbells. We can therefore drop
the doorbell code we currently have, also given the fact that in the
unlikely case we'd want to switch back to using doorbells we'd have to
heavily rework it.
The workqueue will still have a use in the new interface to pass special
commands, so that code has been retained for now.
With the doorbells gone and the GuC client becoming even simpler, the
existing GuC selftests don't give us any meaningful coverage so we can
remove them as well. Some selftests might come with the new code, but
they will look different from what we have now so if doesn't seem worth
it to keep the file around in the meantime.
v2: fix comments and commit message (John)
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: John Harrison <John.C.Harrison@Intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191205220243.27403-3-daniele.ceraolospurio@intel.com
Being part of the GT HW, it make sense to keep the guc/huc structures
inside the GT structure. To help with the encapsulation work done by the
following patches, both structures are placed inside a new intel_uc
container. Although this results in code with ugly nested dereferences
(i915->gt.uc.guc...), it saves us the extra work required in moving
the structures twice (i915 -> gt -> uc). The following patches will
reduce the number of places where we try to access the guc/huc
structures directly from i915 and reduce the ugliness.
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190713100016.8026-7-chris@chris-wilson.co.uk
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
