[Intel-gfx] [PATCH 6/7] drm/i915/perf: add interrupt enabling parameter

[Umesh Nerlige Ramappa]

On Tue, Mar 03, 2020 at 02:19:04PM -0800, Umesh Nerlige Ramappa wrote:
>From: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
>
>This let's the application choose to be driven by the interrupt
>mechanism of the HW. In conjuction with long periods for checks for
>the availability of data on the CPU, this can reduce the CPU load when
>doing capture of OA data.
>
>v2: Version the new parameter (Joonas)
>v3: Rebase (Umesh)
>
>Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
>Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
>---
> drivers/gpu/drm/i915/i915_perf.c | 58 +++++++++++++++++++++++---------
> include/uapi/drm/i915_drm.h      | 10 ++++++
> 2 files changed, 53 insertions(+), 15 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
>index 502961da840d..ab41cba85b40 100644
>--- a/drivers/gpu/drm/i915/i915_perf.c
>+++ b/drivers/gpu/drm/i915/i915_perf.c
>@@ -252,7 +252,7 @@
>  * oa_buffer_check().
>  *
>  * Most of the implementation details for this workaround are in
>- * oa_buffer_check_unlocked() and _append_oa_reports()
>+ * oa_buffer_check() and _append_oa_reports()
>  *
>  * Note for posterity: previously the driver used to define an effective tail
>  * pointer that lagged the real pointer by a 'tail margin' measured in bytes
>@@ -447,8 +447,9 @@ static u32 gen7_oa_hw_tail_read(struct i915_perf_stream *stream)
> }
>
> /**
>- * oa_buffer_check_unlocked - check for data and update tail ptr state
>+ * oa_buffer_check - check for data and update tail ptr state
>  * @stream: i915 stream instance
>+ * @lock: whether to take the oa_buffer spin lock
>  *
>  * This is either called via fops (for blocking reads in user ctx) or the poll
>  * check hrtimer (atomic ctx) to check the OA buffer tail pointer and check
>@@ -470,8 +471,9 @@ static u32 gen7_oa_hw_tail_read(struct i915_perf_stream *stream)
>  *
>  * Returns: %true if the OA buffer contains data, else %false
>  */
>-static bool oa_buffer_check_unlocked(struct i915_perf_stream *stream)
>+static bool oa_buffer_check(struct i915_perf_stream *stream, bool lock)

Hi Lionel,

All callers seem to set the lock to true when calling oa_buffer_check().  
Do you recall why the parameter was introduced?  If not, we probably 
want to remove this change.

Thanks,
Umesh