With GuC handling scheduling, i915 is not aware of the time that a
context is scheduled in and out of the engine. Since i915 pmu relies on
this info to provide engine busyness to the user, GuC shares this info
with i915 for all engines using shared memory. For each engine, this
info contains:
- total busyness: total time that the context was running (total)
- id: id of the running context (id)
- start timestamp: timestamp when the context started running (start)
At the time (now) of sampling the engine busyness, if the id is valid
(!= ~0), and start is non-zero, then the context is considered to be
active and the engine busyness is calculated using the below equation
engine busyness = total + (now - start)
All times are obtained from the gt clock base. For inactive contexts,
engine busyness is just equal to the total.
The start and total values provided by GuC are 32 bits and wrap around
in a few minutes. Since perf pmu provides busyness as 64 bit
monotonically increasing values, there is a need for this implementation
to account for overflows and extend the time to 64 bits before returning
busyness to the user. In order to do that, a worker runs periodically at
frequency = 1/8th the time it takes for the timestamp to wrap. As an
example, that would be once in 27 seconds for a gt clock frequency of
19.2 MHz.
Note:
There might be an over-accounting of busyness due to the fact that GuC
may be updating the total and start values while kmd is reading them.
(i.e kmd may read the updated total and the stale start). In such a
case, user may see higher busyness value followed by smaller ones which
would eventually catch up to the higher value.
v2: (Tvrtko)
- Include details in commit message
- Move intel engine busyness function into execlist code
- Use union inside engine->stats
- Use natural type for ping delay jiffies
- Drop active_work condition checks
- Use for_each_engine if iterating all engines
- Drop seq locking, use spinlock at GuC level to update engine stats
- Document worker specific details
v3: (Tvrtko/Umesh)
- Demarcate GuC and execlist stat objects with comments
- Document known over-accounting issue in commit
- Provide a consistent view of GuC state
- Add hooks to gt park/unpark for GuC busyness
- Stop/start worker in gt park/unpark path
- Drop inline
- Move spinlock and worker inits to GuC initialization
- Drop helpers that are called only once
v4: (Tvrtko/Matt/Umesh)
- Drop addressed opens from commit message
- Get runtime pm in ping, remove from the park path
- Use cancel_delayed_work_sync in disable_submission path
- Update stats during reset prepare
- Skip ping if reset in progress
- Explicitly name execlists and GuC stats objects
- Since disable_submission is called from many places, move resetting
stats to intel_guc_submission_reset_prepare
v5: (Tvrtko)
- Add a trylock helper that does not sleep and synchronize PMU event
callbacks and worker with gt reset
v6: (CI BAT failures)
- DUTs using execlist submission failed to boot since __gt_unpark is
called during i915 load. This ends up calling the GuC busyness unpark
hook and results in kick-starting an uninitialized worker. Let
park/unpark hooks check if GuC submission has been initialized.
- drop cant_sleep() from trylock helper since rcu_read_lock takes care
of that.
v7: (CI) Fix igt@i915_selftest@live@gt_engines
- For GuC mode of submission the engine busyness is derived from gt time
domain. Use gt time elapsed as reference in the selftest.
- Increase busyness calculation to 10ms duration to ensure batch runs
longer and falls within the busyness tolerances in selftest.
v8:
- Use ktime_get in selftest as before
- intel_reset_trylock_no_wait results in a lockdep splat that is not
trivial to fix since the PMU callback runs in irq context and the
reset paths are tightly knit into the driver. The test that uncovers
this is igt@perf_pmu@faulting-read. Drop intel_reset_trylock_no_wait,
instead use the reset_count to synchronize with gt reset during pmu
callback. For the ping, continue to use intel_reset_trylock since ping
is not run in irq context.
- GuC PM timestamp does not tick when GuC is idle. This can potentially
result in wrong busyness values when a context is active on the
engine, but GuC is idle. Use the RING TIMESTAMP as GPU timestamp to
process the GuC busyness stats. This works since both GuC timestamp and
RING timestamp are synced with the same clock.
- The busyness stats may get updated after the batch starts running.
This delay causes the busyness reported for 100us duration to fall
below 95% in the selftest. The only option at this time is to wait for
GuC busyness to change from idle to active before we sample busyness
over a 100us period.
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211027004821.66097-2-umesh.nerlige.ramappa@intel.com
Add multi-lrc context registration H2G. In addition a workqueue and
process descriptor are setup during multi-lrc context registration as
these data structures are needed for multi-lrc submission.
v2:
(John Harrison)
- Move GuC specific fields into sub-struct
- Clean up WQ defines
- Add comment explaining math to derive WQ / PD address
v3:
(John Harrison)
- Add PARENT_SCRATCH_SIZE define
- Update comment explaining multi-lrc register
v4:
(John Harrison)
- Move PARENT_SCRATCH_SIZE to common file
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/20211014172005.27155-9-matthew.brost@intel.com
Nested grids in grid-table cells are not specified as proper ReST
constructs.
Commit 572f2a5cd9 ("drm/i915/guc: Update firmware to v62.0.0")
added a couple of kerneldoc tables of the form:
+---+-------+------------------------------------------------------+
| 1 | 31:0 | +------------------------------------------------+ |
+---+-------+ | | |
|...| | | Embedded `HXG Message`_ | |
+---+-------+ | | |
| n | 31:0 | +------------------------------------------------+ |
+---+-------+------------------------------------------------------+
For "make htmldocs", they happen to work as one might expect,
but they are incompatible with "make latexdocs" and "make pdfdocs",
and cause the generated gpu.tex file to become incomplete and
unbuildable by xelatex.
Restore the compatibility by removing those nested grids in the tables.
Size comparison of generated gpu.tex:
Sphinx 2.4.4 Sphinx 4.2.0
v5.14: 3238686 3841631
v5.15-rc1: 376270 432729
with this fix: 3377846 3998095
Fixes: 572f2a5cd9 ("drm/i915/guc: Update firmware to v62.0.0")
Cc: John Harrison <John.C.Harrison@Intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/4a227569-074f-c501-58bb-d0d8f60a8ae9@gmail.com
This feature hands over the control of HW RC6 to the GuC.
GuC decides when to put HW into RC6 based on it's internal
busyness algorithms.
GuCRC needs GuC submission to be enabled, and only
supported on Gen12+ for now.
When GuCRC is enabled, do not set HW RC6. Use a H2G message
to tell GuC to enable GuCRC. When disabling RC6, tell GuC to
revert RC6 control back to KMD. KMD is still responsible for
enabling everything related to Coarse Power Gating though.
v2: Address comments (Michal W)
v3: Don't set hysterisis values when GuCRC is used (Matt Roper)
v4: checkpatch()
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210730202119.23810-15-vinay.belgaumkar@intel.com
The new GuC interface introduces an MMIO H2G command,
INTEL_GUC_ACTION_RESET_CLIENT, which is used to implement suspend. This
MMIO tears down any active contexts generating a context reset G2H CTB
for each. Once that step completes the GuC tears down the CTB
channels. It is safe to suspend once this MMIO H2G command completes
and all G2H CTBs have been processed. In practice the i915 will likely
never receive a G2H as suspend should only be called after the GPU is
idle.
Resume is implemented in the same manner as before - simply reload the
GuC firmware and reinitialize everything (e.g. CTB channels, contexts,
etc..).
v2:
(Michel / John H)
- INTEL_GUC_ACTION_RESET_CLIENT 0x5B01 -> 0x5507
Cc: John Harrison <john.c.harrison@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@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/20210727002348.97202-12-matthew.brost@intel.com
Add non blocking CTB send function, intel_guc_send_nb. GuC submission
will send CTBs in the critical path and does not need to wait for these
CTBs to complete before moving on, hence the need for this new function.
The non-blocking CTB now must have a flow control mechanism to ensure
the buffer isn't overrun. A lazy spin wait is used as we believe the
flow control condition should be rare with a properly sized buffer.
The function, intel_guc_send_nb, is exported in this patch but unused.
Several patches later in the series make use of this function.
v2:
(Michal)
- Use define for H2G room calculations
- Move INTEL_GUC_SEND_NB define
(Daniel Vetter)
- Use msleep_interruptible rather than cond_resched
v3:
(Michal)
- Move includes to following patch
- s/INTEL_GUC_SEND_NB/INTEL_GUC_CT_SEND_NB/g
v4:
(John H)
- Update comment, add type local variable
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
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/20210708162055.129996-5-matthew.brost@intel.com
