From: Robert Bragg Date: Thu, 11 May 2017 15:43:30 +0000 (+0100) Subject: drm/i915/perf: better pipeline aged/aging tail updates X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=4117ebc74cb3ca25966488b8da6157a299f02e92;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git drm/i915/perf: better pipeline aged/aging tail updates This updates the tail pointer race workaround handling to updating the 'aged' pointer before looking to start aging a new one. There's the possibility that there is already new data available and so we can immediately start aging a new pointer without having to first wait for a later hrtimer callback (and then another to age). Signed-off-by: Robert Bragg Reviewed-by: Matthew Auld Link: http://patchwork.freedesktop.org/patch/msgid/20170511154345.962-8-lionel.g.landwerlin@intel.com Signed-off-by: Chris Wilson --- diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c index 957b959ea67d..4d31b70df452 100644 --- a/drivers/gpu/drm/i915/i915_perf.c +++ b/drivers/gpu/drm/i915/i915_perf.c @@ -391,6 +391,29 @@ static bool gen7_oa_buffer_check_unlocked(struct drm_i915_private *dev_priv) now = ktime_get_mono_fast_ns(); + /* Update the aged tail + * + * Flip the tail pointer available for read()s once the aging tail is + * old enough to trust that the corresponding data will be visible to + * the CPU... + * + * Do this before updating the aging pointer in case we may be able to + * immediately start aging a new pointer too (if new data has become + * available) without needing to wait for a later hrtimer callback. + */ + if (aging_tail != INVALID_TAIL_PTR && + ((now - dev_priv->perf.oa.oa_buffer.aging_timestamp) > + OA_TAIL_MARGIN_NSEC)) { + aged_idx ^= 1; + dev_priv->perf.oa.oa_buffer.aged_tail_idx = aged_idx; + + aged_tail = aging_tail; + + /* Mark that we need a new pointer to start aging... */ + dev_priv->perf.oa.oa_buffer.tails[!aged_idx].offset = INVALID_TAIL_PTR; + aging_tail = INVALID_TAIL_PTR; + } + /* Update the aging tail * * We throttle aging tail updates until we have a new tail that @@ -420,24 +443,6 @@ static bool gen7_oa_buffer_check_unlocked(struct drm_i915_private *dev_priv) } } - /* Update the aged tail - * - * Flip the tail pointer available for read()s once the aging tail is - * old enough to trust that the corresponding data will be visible to - * the CPU... - */ - if (aging_tail != INVALID_TAIL_PTR && - ((now - dev_priv->perf.oa.oa_buffer.aging_timestamp) > - OA_TAIL_MARGIN_NSEC)) { - aged_idx ^= 1; - dev_priv->perf.oa.oa_buffer.aged_tail_idx = aged_idx; - - aged_tail = aging_tail; - - /* Mark that we need a new pointer to start aging... */ - dev_priv->perf.oa.oa_buffer.tails[!aged_idx].offset = INVALID_TAIL_PTR; - } - spin_unlock_irqrestore(&dev_priv->perf.oa.oa_buffer.ptr_lock, flags); return aged_tail == INVALID_TAIL_PTR ?