[PATCH 1/2] drm/amdgpu: Convert to common fdinfo format v5

Sharma, Shashank shashank.sharma at amd.com
Tue May 17 17:49:34 UTC 2022


Please feel free to use:
Reviewed-by: Shashank Sharma <shashank.sharma at amd.com>

On 5/17/2022 12:36 PM, Christian König wrote:
> Convert fdinfo format to one documented in drm-usage-stats.rst.
> 
> It turned out that the existing implementation was actually completely
> nonsense. The calculated percentages indeed represented the usage of the
> engine, but with varying time slices.
> 
> So 10% usage for application A could mean something completely different
> than 10% usage for application B.
> 
> Completely nuke that and just use the now standardized nanosecond
> interface.
> 
> v2: drop the documentation change for now, nuke percentage calculation
> v3: only account for each hw_ip, move the time_spend to the ctx mgr.
> v4: move general ctx changes into separate patch, rework the fdinfo to
>      ctx_mgr interface so that all usages are calculated at once, drop
>      some unecessary and dangerous refcount dance.
> v5: add one more comment how we calculate the time spend
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> Cc: Daniel Vetter <daniel at ffwll.ch>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c    | 177 +++++++++++----------
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h    |  12 +-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c |  57 +++----
>   3 files changed, 125 insertions(+), 121 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
> index a5fef5213fc5..a1d5275a2e78 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
> @@ -162,17 +162,50 @@ static unsigned int amdgpu_ctx_get_hw_prio(struct amdgpu_ctx *ctx, u32 hw_ip)
>   	return hw_prio;
>   }
>   
> +/* Calculate the time spend on the hw */
> +static ktime_t amdgpu_ctx_fence_time(struct dma_fence *fence)
> +{
> +	struct drm_sched_fence *s_fence;
> +
> +	if (!fence)
> +		return ns_to_ktime(0);
> +
> +	/* When the fence is not even scheduled it can't have spend time */
> +	s_fence = to_drm_sched_fence(fence);
> +	if (!test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &s_fence->scheduled.flags))
> +		return ns_to_ktime(0);
> +
> +	/* When it is still running account how much already spend */
> +	if (!test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &s_fence->finished.flags))
> +		return ktime_sub(ktime_get(), s_fence->scheduled.timestamp);
> +
> +	return ktime_sub(s_fence->finished.timestamp,
> +			 s_fence->scheduled.timestamp);
> +}
> +
> +static ktime_t amdgpu_ctx_entity_time(struct amdgpu_ctx *ctx,
> +				      struct amdgpu_ctx_entity *centity)
> +{
> +	ktime_t res = ns_to_ktime(0);
> +	uint32_t i;
> +
> +	spin_lock(&ctx->ring_lock);
> +	for (i = 0; i < amdgpu_sched_jobs; i++) {
> +		res = ktime_add(res, amdgpu_ctx_fence_time(centity->fences[i]));
> +	}
> +	spin_unlock(&ctx->ring_lock);
> +	return res;
> +}
>   
>   static int amdgpu_ctx_init_entity(struct amdgpu_ctx *ctx, u32 hw_ip,
>   				  const u32 ring)
>   {
> +	struct drm_gpu_scheduler **scheds = NULL, *sched = NULL;
>   	struct amdgpu_device *adev = ctx->mgr->adev;
>   	struct amdgpu_ctx_entity *entity;
> -	struct drm_gpu_scheduler **scheds = NULL, *sched = NULL;
> -	unsigned num_scheds = 0;
> -	int32_t ctx_prio;
> -	unsigned int hw_prio;
>   	enum drm_sched_priority drm_prio;
> +	unsigned int hw_prio, num_scheds;
> +	int32_t ctx_prio;
>   	int r;
>   
>   	entity = kzalloc(struct_size(entity, fences, amdgpu_sched_jobs),
> @@ -182,6 +215,7 @@ static int amdgpu_ctx_init_entity(struct amdgpu_ctx *ctx, u32 hw_ip,
>   
>   	ctx_prio = (ctx->override_priority == AMDGPU_CTX_PRIORITY_UNSET) ?
>   			ctx->init_priority : ctx->override_priority;
> +	entity->hw_ip = hw_ip;
>   	entity->sequence = 1;
>   	hw_prio = amdgpu_ctx_get_hw_prio(ctx, hw_ip);
>   	drm_prio = amdgpu_ctx_to_drm_sched_prio(ctx_prio);
> @@ -220,6 +254,23 @@ static int amdgpu_ctx_init_entity(struct amdgpu_ctx *ctx, u32 hw_ip,
>   	return r;
>   }
>   
> +static ktime_t amdgpu_ctx_fini_entity(struct amdgpu_ctx_entity *entity)
> +{
> +	ktime_t res = ns_to_ktime(0);
> +	int i;
> +
> +	if (!entity)
> +		return res;
> +
> +	for (i = 0; i < amdgpu_sched_jobs; ++i) {
> +		res = ktime_add(res, amdgpu_ctx_fence_time(entity->fences[i]));
> +		dma_fence_put(entity->fences[i]);
> +	}
> +
> +	kfree(entity);
> +	return res;
> +}
> +
>   static int amdgpu_ctx_init(struct amdgpu_ctx_mgr *mgr, int32_t priority,
>   			   struct drm_file *filp, struct amdgpu_ctx *ctx)
>   {
> @@ -245,20 +296,6 @@ static int amdgpu_ctx_init(struct amdgpu_ctx_mgr *mgr, int32_t priority,
>   	return 0;
>   }
>   
> -static void amdgpu_ctx_fini_entity(struct amdgpu_ctx_entity *entity)
> -{
> -
> -	int i;
> -
> -	if (!entity)
> -		return;
> -
> -	for (i = 0; i < amdgpu_sched_jobs; ++i)
> -		dma_fence_put(entity->fences[i]);
> -
> -	kfree(entity);
> -}
> -
>   static int amdgpu_ctx_get_stable_pstate(struct amdgpu_ctx *ctx,
>   					u32 *stable_pstate)
>   {
> @@ -350,8 +387,10 @@ static void amdgpu_ctx_fini(struct kref *ref)
>   
>   	for (i = 0; i < AMDGPU_HW_IP_NUM; ++i) {
>   		for (j = 0; j < AMDGPU_MAX_ENTITY_NUM; ++j) {
> -			amdgpu_ctx_fini_entity(ctx->entities[i][j]);
> -			ctx->entities[i][j] = NULL;
> +			ktime_t spend;
> +
> +			spend = amdgpu_ctx_fini_entity(ctx->entities[i][j]);
> +			atomic64_add(ktime_to_ns(spend), &mgr->time_spend[i]);
>   		}
>   	}
>   
> @@ -687,6 +726,9 @@ uint64_t amdgpu_ctx_add_fence(struct amdgpu_ctx *ctx,
>   	centity->sequence++;
>   	spin_unlock(&ctx->ring_lock);
>   
> +	atomic64_add(ktime_to_ns(amdgpu_ctx_fence_time(other)),
> +		     &ctx->mgr->time_spend[centity->hw_ip]);
> +
>   	dma_fence_put(other);
>   	return seq;
>   }
> @@ -793,9 +835,14 @@ int amdgpu_ctx_wait_prev_fence(struct amdgpu_ctx *ctx,
>   void amdgpu_ctx_mgr_init(struct amdgpu_ctx_mgr *mgr,
>   			 struct amdgpu_device *adev)
>   {
> +	unsigned int i;
> +
>   	mgr->adev = adev;
>   	mutex_init(&mgr->lock);
>   	idr_init(&mgr->ctx_handles);
> +
> +	for (i = 0; i < AMDGPU_HW_IP_NUM; ++i)
> +		atomic64_set(&mgr->time_spend[i], 0);
>   }
>   
>   long amdgpu_ctx_mgr_entity_flush(struct amdgpu_ctx_mgr *mgr, long timeout)
> @@ -871,80 +918,38 @@ void amdgpu_ctx_mgr_fini(struct amdgpu_ctx_mgr *mgr)
>   	mutex_destroy(&mgr->lock);
>   }
>   
> -static void amdgpu_ctx_fence_time(struct amdgpu_ctx *ctx,
> -		struct amdgpu_ctx_entity *centity, ktime_t *total, ktime_t *max)
> -{
> -	ktime_t now, t1;
> -	uint32_t i;
> -
> -	*total = *max = 0;
> -
> -	now = ktime_get();
> -	for (i = 0; i < amdgpu_sched_jobs; i++) {
> -		struct dma_fence *fence;
> -		struct drm_sched_fence *s_fence;
> -
> -		spin_lock(&ctx->ring_lock);
> -		fence = dma_fence_get(centity->fences[i]);
> -		spin_unlock(&ctx->ring_lock);
> -		if (!fence)
> -			continue;
> -		s_fence = to_drm_sched_fence(fence);
> -		if (!dma_fence_is_signaled(&s_fence->scheduled)) {
> -			dma_fence_put(fence);
> -			continue;
> -		}
> -		t1 = s_fence->scheduled.timestamp;
> -		if (!ktime_before(t1, now)) {
> -			dma_fence_put(fence);
> -			continue;
> -		}
> -		if (dma_fence_is_signaled(&s_fence->finished) &&
> -			s_fence->finished.timestamp < now)
> -			*total += ktime_sub(s_fence->finished.timestamp, t1);
> -		else
> -			*total += ktime_sub(now, t1);
> -		t1 = ktime_sub(now, t1);
> -		dma_fence_put(fence);
> -		*max = max(t1, *max);
> -	}
> -}
> -
> -ktime_t amdgpu_ctx_mgr_fence_usage(struct amdgpu_ctx_mgr *mgr, uint32_t hwip,
> -		uint32_t idx, uint64_t *elapsed)
> +void amdgpu_ctx_mgr_usage(struct amdgpu_ctx_mgr *mgr,
> +			  ktime_t usage[AMDGPU_HW_IP_NUM])
>   {
> -	struct idr *idp;
>   	struct amdgpu_ctx *ctx;
> +	unsigned int hw_ip, i;
>   	uint32_t id;
> -	struct amdgpu_ctx_entity *centity;
> -	ktime_t total = 0, max = 0;
>   
> -	if (idx >= AMDGPU_MAX_ENTITY_NUM)
> -		return 0;
> -	idp = &mgr->ctx_handles;
> +	/*
> +	 * This is a little bit racy because it can be that a ctx or a fence are
> +	 * destroyed just in the moment we try to account them. But that is ok
> +	 * since exactly that case is explicitely allowed by the interface.
> +	 */
>   	mutex_lock(&mgr->lock);
> -	idr_for_each_entry(idp, ctx, id) {
> -		ktime_t ttotal, tmax;
> +	for (hw_ip = 0; hw_ip < AMDGPU_HW_IP_NUM; ++hw_ip) {
> +		uint64_t ns = atomic64_read(&mgr->time_spend[hw_ip]);
>   
> -		if (!ctx->entities[hwip][idx])
> -			continue;
> +		usage[hw_ip] = ns_to_ktime(ns);
> +	}
>   
> -		centity = ctx->entities[hwip][idx];
> -		amdgpu_ctx_fence_time(ctx, centity, &ttotal, &tmax);
> +	idr_for_each_entry(&mgr->ctx_handles, ctx, id) {
> +		for (hw_ip = 0; hw_ip < AMDGPU_HW_IP_NUM; ++hw_ip) {
> +			for (i = 0; i < amdgpu_ctx_num_entities[hw_ip]; ++i) {
> +				struct amdgpu_ctx_entity *centity;
> +				ktime_t spend;
>   
> -		/* Harmonic mean approximation diverges for very small
> -		 * values. If ratio < 0.01% ignore
> -		 */
> -		if (AMDGPU_CTX_FENCE_USAGE_MIN_RATIO(tmax, ttotal))
> -			continue;
> -
> -		total = ktime_add(total, ttotal);
> -		max = ktime_after(tmax, max) ? tmax : max;
> +				centity = ctx->entities[hw_ip][i];
> +				if (!centity)
> +					continue;
> +				spend = amdgpu_ctx_entity_time(ctx, centity);
> +				usage[hw_ip] = ktime_add(usage[hw_ip], spend);
> +			}
> +		}
>   	}
> -
>   	mutex_unlock(&mgr->lock);
> -	if (elapsed)
> -		*elapsed = max;
> -
> -	return total;
>   }
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h
> index 3ceebab9c6ea..0fa0e56daf67 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h
> @@ -23,16 +23,20 @@
>   #ifndef __AMDGPU_CTX_H__
>   #define __AMDGPU_CTX_H__
>   
> +#include <linux/ktime.h>
> +#include <linux/types.h>
> +
>   #include "amdgpu_ring.h"
>   
>   struct drm_device;
>   struct drm_file;
>   struct amdgpu_fpriv;
> +struct amdgpu_ctx_mgr;
>   
>   #define AMDGPU_MAX_ENTITY_NUM 4
> -#define AMDGPU_CTX_FENCE_USAGE_MIN_RATIO(max, total) ((max) > 16384ULL*(total))
>   
>   struct amdgpu_ctx_entity {
> +	uint32_t		hw_ip;
>   	uint64_t		sequence;
>   	struct drm_sched_entity	entity;
>   	struct dma_fence	*fences[];
> @@ -60,6 +64,7 @@ struct amdgpu_ctx_mgr {
>   	struct mutex		lock;
>   	/* protected by lock */
>   	struct idr		ctx_handles;
> +	atomic64_t		time_spend[AMDGPU_HW_IP_NUM];
>   };
>   
>   extern const unsigned int amdgpu_ctx_num_entities[AMDGPU_HW_IP_NUM];
> @@ -89,6 +94,7 @@ void amdgpu_ctx_mgr_init(struct amdgpu_ctx_mgr *mgr,
>   void amdgpu_ctx_mgr_entity_fini(struct amdgpu_ctx_mgr *mgr);
>   long amdgpu_ctx_mgr_entity_flush(struct amdgpu_ctx_mgr *mgr, long timeout);
>   void amdgpu_ctx_mgr_fini(struct amdgpu_ctx_mgr *mgr);
> -ktime_t amdgpu_ctx_mgr_fence_usage(struct amdgpu_ctx_mgr *mgr, uint32_t hwip,
> -		uint32_t idx, uint64_t *elapsed);
> +void amdgpu_ctx_mgr_usage(struct amdgpu_ctx_mgr *mgr,
> +			  ktime_t usage[AMDGPU_HW_IP_NUM]);
> +
>   #endif
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c
> index 5a6857c44bb6..4d453845235c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c
> @@ -32,6 +32,7 @@
>   
>   #include <drm/amdgpu_drm.h>
>   #include <drm/drm_debugfs.h>
> +#include <drm/drm_drv.h>
>   
>   #include "amdgpu.h"
>   #include "amdgpu_vm.h"
> @@ -54,26 +55,23 @@ static const char *amdgpu_ip_name[AMDGPU_HW_IP_NUM] = {
>   
>   void amdgpu_show_fdinfo(struct seq_file *m, struct file *f)
>   {
> -	struct amdgpu_fpriv *fpriv;
> -	uint32_t bus, dev, fn, i, domain;
> -	uint64_t vram_mem = 0, gtt_mem = 0, cpu_mem = 0;
>   	struct drm_file *file = f->private_data;
>   	struct amdgpu_device *adev = drm_to_adev(file->minor->dev);
> +	struct amdgpu_fpriv *fpriv = file->driver_priv;
> +
> +	uint64_t vram_mem = 0, gtt_mem = 0, cpu_mem = 0;
> +	ktime_t usage[AMDGPU_HW_IP_NUM];
> +	uint32_t bus, dev, fn, domain;
>   	struct amdgpu_bo *root;
> +	unsigned int hw_ip;
>   	int ret;
>   
> -	ret = amdgpu_file_to_fpriv(f, &fpriv);
> -	if (ret)
> -		return;
>   	bus = adev->pdev->bus->number;
>   	domain = pci_domain_nr(adev->pdev->bus);
>   	dev = PCI_SLOT(adev->pdev->devfn);
>   	fn = PCI_FUNC(adev->pdev->devfn);
>   
> -	root = amdgpu_bo_ref(fpriv->vm.root.bo);
> -	if (!root)
> -		return;
> -
> +	root = fpriv->vm.root.bo;
>   	ret = amdgpu_bo_reserve(root, false);
>   	if (ret) {
>   		DRM_ERROR("Fail to reserve bo\n");
> @@ -81,31 +79,26 @@ void amdgpu_show_fdinfo(struct seq_file *m, struct file *f)
>   	}
>   	amdgpu_vm_get_memory(&fpriv->vm, &vram_mem, &gtt_mem, &cpu_mem);
>   	amdgpu_bo_unreserve(root);
> -	amdgpu_bo_unref(&root);
>   
> -	seq_printf(m, "pdev:\t%04x:%02x:%02x.%d\npasid:\t%u\n", domain, bus,
> -			dev, fn, fpriv->vm.pasid);
> -	seq_printf(m, "vram mem:\t%llu kB\n", vram_mem/1024UL);
> -	seq_printf(m, "gtt mem:\t%llu kB\n", gtt_mem/1024UL);
> -	seq_printf(m, "cpu mem:\t%llu kB\n", cpu_mem/1024UL);
> -	for (i = 0; i < AMDGPU_HW_IP_NUM; i++) {
> -		uint32_t count = amdgpu_ctx_num_entities[i];
> -		int idx = 0;
> -		uint64_t total = 0, min = 0;
> -		uint32_t perc, frac;
> +	amdgpu_ctx_mgr_usage(&fpriv->ctx_mgr, usage);
>   
> -		for (idx = 0; idx < count; idx++) {
> -			total = amdgpu_ctx_mgr_fence_usage(&fpriv->ctx_mgr,
> -				i, idx, &min);
> -			if ((total == 0) || (min == 0))
> -				continue;
> +	/*
> +	 * ******************************************************************
> +	 * For text output format description please see drm-usage-stats.rst!
> +	 * ******************************************************************
> +	 */
>   
> -			perc = div64_u64(10000 * total, min);
> -			frac = perc % 100;
> +	seq_printf(m, "pasid:\t%u\n", fpriv->vm.pasid);
> +	seq_printf(m, "drm-driver:\t%s\n", file->minor->dev->driver->name);
> +	seq_printf(m, "drm-pdev:\t%04x:%02x:%02x.%d\n", domain, bus, dev, fn);
> +	seq_printf(m, "drm-memory-vram:\t%llu KiB\n", vram_mem/1024UL);
> +	seq_printf(m, "drm-memory-gtt: \t%llu KiB\n", gtt_mem/1024UL);
> +	seq_printf(m, "drm-memory-cpu: \t%llu KiB\n", cpu_mem/1024UL);
> +	for (hw_ip = 0; hw_ip < AMDGPU_HW_IP_NUM; ++hw_ip) {
> +		if (!usage[hw_ip])
> +			continue;
>   
> -			seq_printf(m, "%s%d:\t%d.%d%%\n",
> -					amdgpu_ip_name[i],
> -					idx, perc/100, frac);
> -		}
> +		seq_printf(m, "drm-engine-%s:\t%Ld ns\n", amdgpu_ip_name[hw_ip],
> +			   ktime_to_ns(usage[hw_ip]));
>   	}
>   }


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