[Intel-gfx] [PATCH 0/9] Enable Gen 7 Observation Architecture

[Robert Bragg]

I've been working on some i-g-t tests for this new interface and while I still
have some more tests to write, it still seemed worth sending out another updated
series in the mean time.


Firstly this includes updates based on Emil's previous comments.

Then there have been a few issue hit while writing tests:

* It seems it can take a fairly long time for the MUX config to apply after
  the register writes have finished, and now the driver inserts a delay after
  configuration, before enabling periodic sampling.
* I've found that sometimes the HW tail pointer can get ahead of OA buffer
  writes, especially with higher sampling frequencies, and so now the driver
  maintains a margin behind the HW tail pointer to ensure the most recent
  reports have some time to land before attempting to copy them to userspace.
* As a sanity check that a report is valid before it's copied to userspace the
  driver checks the report-id field != 0
* The _BUFFER_OVERFLOW record has been replaced with a _BUFFER_LOST record with
  more specific semantics.
* Since we can't clear the overflow status on Haswell while periodic sampling
  is enabled, if an overflow occurs we now restart the unit.
* The maximum OA periodic sampling exponent is now 31
* We verify the head/tail pointers read back from HW look sane before using as
  offsets to read reports from the OA buffer. We reset the HW if they look bad.


For reference the work-in-progress i-g-t tests can be found here:

https://github.com/rib/intel-gpu-tools
branch = wip/rib/i915-perf-tests

or browsed here:
https://github.com/rib/intel-gpu-tools/commits/wip/rib/i915-perf-tests

Also for reference these patches can be fetched from here:

https://github.com/rib/linux
branch = wip/rib/oa-2016-04-19-nightly

Regards,
- Robert


Robert Bragg (9):
  drm/i915: Add i915 perf infrastructure
  drm/i915: rename OACONTROL GEN7_OACONTROL
  drm/i915: don't whitelist oacontrol in cmd parser
  drm/i915: Add 'render basic' Haswell OA unit config
  drm/i915: Enable i915 perf stream for Haswell OA unit
  drm/i915: advertise available metrics via sysfs
  drm/i915: Add dev.i915.perf_event_paranoid sysctl option
  drm/i915: add oa_event_min_timer_exponent sysctl
  drm/i915: Add more Haswell OA metric sets

 drivers/gpu/drm/i915/Makefile           |    4 +
 drivers/gpu/drm/i915/i915_cmd_parser.c  |   33 +-
 drivers/gpu/drm/i915/i915_dma.c         |    8 +
 drivers/gpu/drm/i915/i915_drv.h         |  155 ++++
 drivers/gpu/drm/i915/i915_gem_context.c |   24 +-
 drivers/gpu/drm/i915/i915_oa_hsw.c      |  658 ++++++++++++++
 drivers/gpu/drm/i915/i915_oa_hsw.h      |   38 +
 drivers/gpu/drm/i915/i915_perf.c        | 1439 +++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_reg.h         |  340 +++++++-
 include/uapi/drm/i915_drm.h             |  133 +++
 10 files changed, 2795 insertions(+), 37 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/i915_oa_hsw.c
 create mode 100644 drivers/gpu/drm/i915/i915_oa_hsw.h
 create mode 100644 drivers/gpu/drm/i915/i915_perf.c

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2.7.1