[RFC,v2,0/4] Expose RPS thresholds in sysfs

Message

Tvrtko Ursulin April 28, 2023, 8:14 a.m. UTC

From: Tvrtko Ursulin <[e-mail]>

From patch 4:

    User feedback indicates significant performance gains are possible in
    specific games with non default RPS up/down thresholds.

    Expose these tunables via sysfs which will allow users to achieve best
    performance when running games and best power efficiency elsewhere.

    Note this patch supports non GuC based platforms only.

    References: https://gitlab.freedesktop.org/drm/intel/-/issues/8389

Issue 8389 suggests 10-15% performance gains are possible with tweaked
thresholds.

One question is are we able to find a "one size fits all" values.

However regardless of that, given we already expose frequency controls in sysfs
with the same reasoning of allowing system owners explicit control if so wanted,
I think exposing the thresholds can be equally justified.

v2:
 * Hopefully fixed the debug build issue.
 * Re-program the hw registers on change too!

Tvrtko Ursulin (4):
  drm/i915: Move setting of rps thresholds to init
  drm/i915: Record default rps threshold values
  drm/i915: Add helpers for managing rps thresholds
  drm/i915: Expose RPS thresholds in sysfs

 drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c | 104 ++++++++++++++++++++
 drivers/gpu/drm/i915/gt/intel_gt_types.h    |   3 +
 drivers/gpu/drm/i915/gt/intel_rps.c         |  70 ++++++++++---
 drivers/gpu/drm/i915/gt/intel_rps.h         |   4 +
 4 files changed, 170 insertions(+), 11 deletions(-)