Re: [Intel-gfx] [PATCH 10/19] drm/i915/perf: Use gt-specific ggtt for OA and noa-wait buffers

[Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>]

On Tue, Sep 06, 2022 at 10:56:13PM +0300, Lionel Landwerlin wrote:
>On 23/08/2022 23:41, Umesh Nerlige Ramappa wrote:
>>User passes uabi engine class and instance to the perf OA interface. Use
>>gt corresponding to the engine to pin the buffers to the right ggtt.
>>
>>Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
>
>I didn't know there was a GGTT per engine.
>
>Do I understand this correct?

No, GGTT is still per-gt. We just derive the gt from engine class 
instance passed (as in engine->gt).

>
>
>Thanks,
>
>-Lionel
>
>
>>---
>>  drivers/gpu/drm/i915/i915_perf.c | 21 +++++++++++++++++++--
>>  1 file changed, 19 insertions(+), 2 deletions(-)
>>
>>diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
>>index 87b92d2946f4..f7621b45966c 100644
>>--- a/drivers/gpu/drm/i915/i915_perf.c
>>+++ b/drivers/gpu/drm/i915/i915_perf.c
>>@@ -1765,6 +1765,7 @@ static void gen12_init_oa_buffer(struct i915_perf_stream *stream)
>>  static int alloc_oa_buffer(struct i915_perf_stream *stream)
>>  {
>>  	struct drm_i915_private *i915 = stream->perf->i915;
>>+	struct intel_gt *gt = stream->engine->gt;
>>  	struct drm_i915_gem_object *bo;
>>  	struct i915_vma *vma;
>>  	int ret;
>>@@ -1784,11 +1785,22 @@ static int alloc_oa_buffer(struct i915_perf_stream *stream)
>>  	i915_gem_object_set_cache_coherency(bo, I915_CACHE_LLC);
>>  	/* PreHSW required 512K alignment, HSW requires 16M */
>>-	vma = i915_gem_object_ggtt_pin(bo, NULL, 0, SZ_16M, 0);
>>+	vma = i915_vma_instance(bo, &gt->ggtt->vm, NULL);
>>  	if (IS_ERR(vma)) {
>>  		ret = PTR_ERR(vma);
>>  		goto err_unref;
>>  	}
>>+
>>+	/*
>>+	 * PreHSW required 512K alignment.
>>+	 * HSW and onwards, align to requested size of OA buffer.
>>+	 */
>>+	ret = i915_vma_pin(vma, 0, SZ_16M, PIN_GLOBAL | PIN_HIGH);
>>+	if (ret) {
>>+		drm_err(&gt->i915->drm, "Failed to pin OA buffer %d\n", ret);
>>+		goto err_unref;
>>+	}
>>+
>>  	stream->oa_buffer.vma = vma;
>>  	stream->oa_buffer.vaddr =
>>@@ -1838,6 +1850,7 @@ static u32 *save_restore_register(struct i915_perf_stream *stream, u32 *cs,
>>  static int alloc_noa_wait(struct i915_perf_stream *stream)
>>  {
>>  	struct drm_i915_private *i915 = stream->perf->i915;
>>+	struct intel_gt *gt = stream->engine->gt;
>>  	struct drm_i915_gem_object *bo;
>>  	struct i915_vma *vma;
>>  	const u64 delay_ticks = 0xffffffffffffffff -
>>@@ -1878,12 +1891,16 @@ static int alloc_noa_wait(struct i915_perf_stream *stream)
>>  	 * multiple OA config BOs will have a jump to this address and it
>>  	 * needs to be fixed during the lifetime of the i915/perf stream.
>>  	 */
>>-	vma = i915_gem_object_ggtt_pin_ww(bo, &ww, NULL, 0, 0, PIN_HIGH);
>>+	vma = i915_vma_instance(bo, &gt->ggtt->vm, NULL);
>>  	if (IS_ERR(vma)) {
>>  		ret = PTR_ERR(vma);
>>  		goto out_ww;
>>  	}
>>+	ret = i915_vma_pin_ww(vma, &ww, 0, 0, PIN_GLOBAL | PIN_HIGH);
>>+	if (ret)
>>+		goto out_ww;
>>+
>>  	batch = cs = i915_gem_object_pin_map(bo, I915_MAP_WB);
>>  	if (IS_ERR(batch)) {
>>  		ret = PTR_ERR(batch);
>
>