[Intel-gfx] [PATCH 06/19] drm/i915/perf: Use helpers to process reports w.r.t. OA buffer size

Umesh Nerlige Ramappa
2022-08-23T20:42:23Z

DG2 has a new feature to supports OA buffer sizes up to 128Mb by
toggling a bit in OA_DEBUG. This would eventually be a user configurable
parameter. Use OA buffer vma size in all calculations with some helpers.

v2: Let compiler decide inline (Jani)

Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
---
drivers/gpu/drm/i915/i915_perf.c | 46 +++++++++++++++++++++-----------
1 file changed, 31 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 6fc4f0d8fc5a..bbf1c574f393 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -385,6 +385,21 @@ static struct ctl_table_header *sysctl_header;

static enum hrtimer_restart oa_poll_check_timer_cb(struct hrtimer *hrtimer);

+static u32 _oa_taken(struct i915_perf_stream * stream, u32 tail, u32 head)
+{
+ u32 size = stream->oa_buffer.vma->size;
+
+ return tail >= head ? tail - head : size - (head - tail);
+}
+
+static u32 _rewind_tail(struct i915_perf_stream * stream, u32 relative_hw_tail,
+ u32 rewind_delta)
+{
+ return rewind_delta > relative_hw_tail ?
+ stream->oa_buffer.vma->size - (rewind_delta - relative_hw_tail) :
+ relative_hw_tail - rewind_delta;
+}
+
void i915_oa_config_release(struct kref *ref)
{
struct i915_oa_config *oa_config =
@@ -487,12 +502,14 @@ static bool oa_buffer_check_unlocked(struct i915_perf_stream *stream)
* sizes need not be integral multiples or 64 or powers of 2.
* Compute potentially partially landed report in the OA buffer
*/
- partial_report_size = OA_TAKEN(hw_tail, stream->oa_buffer.tail);
+ partial_report_size =
+ _oa_taken(stream, hw_tail, stream->oa_buffer.tail);
partial_report_size %= report_size;

/* Subtract partial amount off the tail */
- hw_tail = gtt_offset + ((hw_tail - partial_report_size) &
- (stream->oa_buffer.vma->size - 1));
+ hw_tail = gtt_offset + _rewind_tail(stream,
+ hw_tail - gtt_offset,
+ partial_report_size);

now = ktime_get_mono_fast_ns();

@@ -527,16 +544,16 @@ static bool oa_buffer_check_unlocked(struct i915_perf_stream *stream)
* memory in the order they were written to.
* If not : (╯°□°）╯︵ ┻━┻
*/
- while (OA_TAKEN(tail, aged_tail) >= report_size) {
+ while (_oa_taken(stream, tail, aged_tail) >= report_size) {
u32 *report32 = (void *)(stream->oa_buffer.vaddr + tail);

if (report32[0] != 0 || report32[1] != 0)
break;

- tail = (tail - report_size) & (OA_BUFFER_SIZE - 1);
+ tail = _rewind_tail(stream, tail, report_size);
}

- if (OA_TAKEN(hw_tail, tail) > report_size &&
+ if (_oa_taken(stream, hw_tail, tail) > report_size &&
__ratelimit(&stream->perf->tail_pointer_race))
DRM_NOTE("unlanded report(s) head=0x%x "
"tail=0x%x hw_tail=0x%x\n",
@@ -547,8 +564,9 @@ static bool oa_buffer_check_unlocked(struct i915_perf_stream *stream)
stream->oa_buffer.aging_timestamp = now;
}

- pollin = OA_TAKEN(stream->oa_buffer.tail - gtt_offset,
- stream->oa_buffer.head - gtt_offset) >= report_size;
+ pollin = _oa_taken(stream,
+ stream->oa_buffer.tail,
+ stream->oa_buffer.head) >= report_size;

spin_unlock_irqrestore(&stream->oa_buffer.ptr_lock, flags);

@@ -679,11 +697,9 @@ static int gen8_append_oa_reports(struct i915_perf_stream *stream,
int report_size = stream->oa_buffer.format_size;
u8 *oa_buf_base = stream->oa_buffer.vaddr;
u32 gtt_offset = i915_ggtt_offset(stream->oa_buffer.vma);
- u32 mask = (OA_BUFFER_SIZE - 1);
size_t start_offset = *offset;
unsigned long flags;
- u32 head, tail;
- u32 taken;
+ u32 head, tail, size;
int ret = 0;

if (drm_WARN_ON(&uncore->i915->drm, !stream->enabled))
@@ -693,6 +709,7 @@ static int gen8_append_oa_reports(struct i915_perf_stream *stream,

head = stream->oa_buffer.head;
tail = stream->oa_buffer.tail;
+ size = stream->oa_buffer.vma->size;

spin_unlock_irqrestore(&stream->oa_buffer.ptr_lock, flags);

@@ -711,16 +728,15 @@ static int gen8_append_oa_reports(struct i915_perf_stream *stream,
* all a power of two).
*/
if (drm_WARN_ONCE(&uncore->i915->drm,
- head > stream->oa_buffer.vma->size ||
- tail > stream->oa_buffer.vma->size,
+ head > size || tail > size,
"Inconsistent OA buffer pointers: head = %u, tail = %u\n",
head, tail))
return -EIO;

for (/* none */;
- (taken = OA_TAKEN(tail, head));
- head = (head + report_size) & mask) {
+ _oa_taken(stream, tail, head);
+ head = (head + report_size) % size) {
u8 *report = oa_buf_base + head;
u32 *report32 = (void *)report;
u32 ctx_id;
--
2.25.1