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  1. 14 Jun, 2017 12 commits
    • Robert Bragg's avatar
      drm/i915/perf: per-gen timebase for checking sample freq · 155e941f
      Robert Bragg authored 
      An oa_exponent_to_ns() utility and per-gen timebase constants where
recently removed when updating the tail pointer race condition WA, and
this restores those so we can update the _PROP_OA_EXPONENT validation
done in read_properties_unlocked() to not assume we have a 12.5MHz
timebase as we did for Haswell.

Accordingly the oa_sample_rate_hard_limit value that's referenced by
proc_dointvec_minmax defining the absolute limit for the OA sampling
frequency is now initialized to (timestamp_frequency / 2) instead of the
6.25MHz constant for Haswell.

v2:
    Specify frequency of 19.2MHz for BXT (Ville)
    Initialize oa_sample_rate_hard_limit per-gen too (Lionel)
Signed-off-by: default avatarRobert Bragg <robert@sixbynine.org>
Signed-off-by: default avatarLionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Signed-off-by: default avatarBen Widawsky <ben@bwidawsk.net>
      155e941f
    • Robert Bragg's avatar
      drm/i915/perf: Add more OA configs for BDW, CHV, SKL + BXT · fc599211
      Robert Bragg authored 
      These are auto generated from an XML description of metric sets,
currently maintained in gputop, ref:

 https://github.com/rib/gputop
 > gputop-data/oa-*.xml
 > scripts/i915-perf-kernelgen.py

 $ make -C gputop-data -f Makefile.xml
Signed-off-by: default avatarRobert Bragg <robert@sixbynine.org>
Signed-off-by: default avatarLionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Signed-off-by: default avatarBen Widawsky <ben@bwidawsk.net>
      fc599211
    • Robert Bragg's avatar
      drm/i915/perf: Add OA unit support for Gen 8+ · 19f81df2
      Robert Bragg authored 
      Enables access to OA unit metrics for BDW, CHV, SKL and BXT which all
share (more-or-less) the same OA unit design.

Of particular note in comparison to Haswell: some OA unit HW config
state has become per-context state and as a consequence it is somewhat
more complicated to manage synchronous state changes from the cpu while
there's no guarantee of what context (if any) is currently actively
running on the gpu.

The periodic sampling frequency which can be particularly useful for
system-wide analysis (as opposed to command stream synchronised
MI_REPORT_PERF_COUNT commands) is perhaps the most surprising state to
have become per-context save and restored (while the OABUFFER
destination is still a shared, system-wide resource).

This support for gen8+ takes care to consider a number of timing
challenges involved in synchronously updating per-context state
primarily by programming all config state from the cpu and updating all
current and saved contexts synchronously while the OA unit is still
disabled.

The driver intentionally avoids depending on command streamer
programming to update OA state considering the lack of synchronization
between the automatic loading of OACTXCONTROL state (that includes the
periodic sampling state and enable state) on context restore and the
parsing of any general purpose BB the driver can control. I.e. this
implementation is careful to avoid the possibility of a context restore
temporarily enabling any out-of-date periodic sampling state. In
addition to the risk of transiently-out-of-date state being loaded
automatically; there are also internal HW latencies involved in the
loading of MUX configurations which would be difficult to account for
from the command streamer (and we only want to enable the unit when once
the MUX configuration is complete).

Since the Gen8+ OA unit design no longer supports clock gating the unit
off for a single given context (which effectively stopped any progress
of counters while any other context was running) and instead supports
tagging OA reports with a context ID for filtering on the CPU, it means
we can no longer hide the system-wide progress of counters from a
non-privileged application only interested in metrics for its own
context. Although we could theoretically try and subtract the progress
of other contexts before forwarding reports via read() we aren't in a
position to filter reports captured via MI_REPORT_PERF_COUNT commands.
As a result, for Gen8+, we always require the
dev.i915.perf_stream_paranoid to be unset for any access to OA metrics
if not root.

v5: Drain submitted requests when enabling metric set to ensure no
    lite-restore erases the context image we just updated (Lionel)

v6: In addition to drain, switch to kernel context & update all
    context in place (Chris)

v7: Add missing mutex_unlock() if switching to kernel context fails
    (Matthew)

v8: Simplify OA period/flex-eu-counters programming by using the
    batchbuffer instead of modifying ctx-image (Lionel)

v9: Back to updating the context image (due to erroneous testing,
    batchbuffer programming the OA unit doesn't actually work)
    (Lionel)
    Pin context before updating context image (Chris)
    Drop MMIO programming now that we switch to a kernel context with
    right values in initial context image (Chris)

v10: Just pin_map the contexts we want to modify or let the
     configuration happen on first use (Chris)

v11: Update kernel context OA config through the batchbuffer rather
     than on the fly ctx-image update (Lionel)

v12: Rework OA context registers update again by swithing away from
     user contexts and reconfiguring the kernel context through the
     batchbuffer and updating all the other contexts' context image.
     Also take care to lock slice/subslice configuration when OA is
     on. (Lionel)

v13: Request rpcs updates on all engine when updating the OA config
     (Lionel)

v14: Drop any kind of rpcs management now that we monitor sseu
     configuration changes in a later patch (Lionel)
     Remove usleep after programming the NOA configs on Gen8+, this
     doesn't seem to be needed (Lionel)

v15: Respect coding style for block comments (Chris)

v16: Add missing i915_add_request() in case we fail to emit OA
     configuration (Matthew)
Signed-off-by: default avatarRobert Bragg <robert@sixbynine.org>
Signed-off-by: default avatarLionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com> \o/
Signed-off-by: default avatarBen Widawsky <ben@bwidawsk.net>
      19f81df2
    • Robert Bragg's avatar
      drm/i915/perf: Add 'render basic' Gen8+ OA unit configs · 5182f646
      Robert Bragg authored 
      Adds a static OA unit, MUX, B Counter + Flex EU configurations for basic
render metrics on Broadwell, Cherryview, Skylake and Broxton. These are
auto generated from an XML description of metric sets, currently
maintained in gputop, ref:

 https://github.com/rib/gputop
 > gputop-data/oa-*.xml
 > scripts/i915-perf-kernelgen.py

 $ make -C gputop-data -f Makefile.xml WHITELIST=RenderBasic

v2: add newlines to debug messages + fix comment (Matthew Auld)
Signed-off-by: default avatarRobert Bragg <robert@sixbynine.org>
Signed-off-by: default avatarLionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Signed-off-by: default avatarBen Widawsky <ben@bwidawsk.net>
      5182f646
    • Lionel Landwerlin's avatar
      drm/i915/perf: rework mux configurations queries · 3f488d99
      Lionel Landwerlin authored 
      Gen8+ might have mux configurations per slices/subslices. Depending on
whether slices/subslices have been fused off, only part of the
configuration needs to be applied. This change reworks the mux
configurations query mechanism to allow more than one set of registers
to be programmed.

v2: s/n_mux_regs/n_mux_configs/ (Matthew)
Signed-off-by: default avatarLionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Signed-off-by: default avatarBen Widawsky <ben@bwidawsk.net>
      3f488d99
    • Robert Bragg's avatar
      drm/i915: expose _SUBSLICE_MASK GETPARM · f5320233
      Robert Bragg authored 
      Assuming a uniform mask across all slices, this enables userspace to
determine the specific sub slices can be enabled. This information is
required, for example, to be able to analyse some OA counter reports
where the counter configuration depends on the HW sub slice
configuration.
Signed-off-by: default avatarRobert Bragg <robert@sixbynine.org>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Signed-off-by: default avatarLionel Landwerlin <lionel.g.landwerlin@intel.com>
Signed-off-by: default avatarBen Widawsky <ben@bwidawsk.net>
      f5320233
    • Robert Bragg's avatar
      drm/i915: expose _SLICE_MASK GETPARM · 7fed555c
      Robert Bragg authored 
      Enables userspace to determine the maximum number of slices that can
be enabled on the device and also know what specific slices can be
enabled. This information is required, for example, to be able to
analyse some OA counter reports where the counter configuration
depends on the HW slice configuration.
Signed-off-by: default avatarRobert Bragg <robert@sixbynine.org>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Signed-off-by: default avatarLionel Landwerlin <lionel.g.landwerlin@intel.com>
Signed-off-by: default avatarBen Widawsky <ben@bwidawsk.net>
      7fed555c
    • Chris Wilson's avatar
      drm/i915: Reinstate reservation_object zapping for batch_pool objects · 9ee82d78
      Chris Wilson authored 
      I removed the zapping of the reservation_object->fence array of shared
fences prematurely. We don't yet have the code to zap that array when
retiring the object, and so currently it remains possible to continually
grow the shared array trapping requests when reusing the batch_pool
object across many timelines.
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170518094638.5469-4-chris@chris-wilson.co.uk
      9ee82d78
    • Chris Wilson's avatar
      drm/i915: Spin for struct_mutex inside shrinker · 290271de
      Chris Wilson authored 
      Having resolved whether or not we would deadlock upon a call to
mutex_lock(&dev->struct_mutex), we can then spin for the contended
struct_mutex if we are not the owner. We cannot afford to simply block
and wait for the mutex, as the owner may itself be waiting for the
allocator -- i.e. a cyclic deadlock. This should significantly improve
the chance of running the shrinker for other processes whilst the GPU is
busy.

A more balanced approach would be to optimistically spin whilst the
mutex owner was on the cpu and there was an opportunity to acquire the
mutex for ourselves quickly. However, that requires support from
kernel/locking/ and a new mutex_spin_trylock() primitive.
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170609110350.1767-4-chris@chris-wilson.co.ukReviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
      290271de
    • Chris Wilson's avatar
      drm/i915: Only restrict noreclaim in the early shrink passes · 0f6ab55d
      Chris Wilson authored 
      In our first pass, we do not want to use reclaim at all as we want to
solely reap the i915 buffer caches (its purgeable pages). But we don't
mind it initiates IO or pulls via the FS (but it shouldn't anyway as we
say no to reclaim!). Just drop the GFP_IO constraint for simplicity.
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170609110350.1767-3-chris@chris-wilson.co.ukReviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
      0f6ab55d
    • Chris Wilson's avatar
      drm/i915: Remove __GFP_NORETRY from our buffer allocator · eaf41801
      Chris Wilson authored 
      I tried __GFP_NORETRY in the belief that __GFP_RECLAIM was effective. It
struggles with handling reclaim of our dirty buffers and relies on
reclaim via kswapd. As a result, a single pass of direct reclaim is
unreliable when i915 occupies the majority of available memory, and the
only means of effectively waiting on kswapd to amke progress is by not
setting the __GFP_NORETRY flag and lopping. That leaves us with the
dilemma of invoking the oomkiller instead of propagating the allocation
failure back to userspace where it can be handled more gracefully (one
hopes).  In the future we may have __GFP_MAYFAIL to allow repeats up until
we genuinely run out of memory and the oomkiller would have been invoked.
Until then, let the oomkiller wreck havoc.

v2: Stop playing with side-effects of gfp flags and await __GFP_MAYFAIL
v3: Update comments that direct reclaim only appears to be ignoring our
dirty buffers!

Fixes: 24f8e00a ("drm/i915: Prefer to report ENOMEM rather than incur the oom for gfx allocations")
Testcase: igt/gem_tiled_swapping
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Michal Hocko <mhocko@suse.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170609110350.1767-2-chris@chris-wilson.co.ukReviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
      eaf41801
    • Chris Wilson's avatar
      drm/i915: Encourage our shrinker more when our shmemfs allocations fails · 4846bf0c
      Chris Wilson authored 
      Commit 24f8e00a ("drm/i915: Prefer to report ENOMEM rather than
incur the oom for gfx allocations") made the bold decision to try and
avoid the oomkiller by reporting -ENOMEM to userspace if our allocation
failed after attempting to free enough buffer objects. In short, it
appears we were giving up too easily (even before we start wondering if
one pass of reclaim is as strong as we would like). Part of the problem
is that if we only shrink just enough pages for our expected allocation,
the likelihood of those pages becoming available to us is less than 100%
To counter-act that we ask for twice the number of pages to be made
available. Furthermore, we allow the shrinker to pull pages from the
active list in later passes.

v2: Be a little more cautious in paging out gfx buffers, and leave that
to a more balanced approach from shrink_slab(). Important when combined
with "drm/i915: Start writeback from the shrinker" as anything shrunk is
immediately swapped out and so should be more conservative.

Fixes: 24f8e00a ("drm/i915: Prefer to report ENOMEM rather than incur the oom for gfx allocations")
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170609110350.1767-1-chris@chris-wilson.co.uk
      4846bf0c
  3. 12 Jun, 2017 23 commits
  5. 09 Jun, 2017 5 commits
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