On Wed, Jul 15, 2015 at 02:21:46PM +0530, sourab.gupta@xxxxxxxxx wrote:
> From: Sourab Gupta <sourab.gupta@xxxxxxxxx>
>
> This patch adds support for retrieving MMIO register values alongwith
> timestamps and forwarding them to userspace through perf.
> The userspace can request upto 8 MMIO register values to be dumped.
> The addresses of upto 8 MMIO registers can be passed through perf attr
> config. The registers are checked against a whitelist before passing them
> on. The commands to dump the values of these MMIO registers are then
> inserted into the ring alongwith commands to dump the timestamps.
>
> Signed-off-by: Sourab Gupta <sourab.gupta@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 2 +
> drivers/gpu/drm/i915/i915_oa_perf.c | 87 ++++++++++++++++++++++++++++++++++---
> include/uapi/drm/i915_drm.h | 10 ++++-
> 3 files changed, 92 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index f2fe8d0..e114175 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2017,7 +2017,9 @@ struct drm_i915_private {
> #define I915_GEN_PMU_SAMPLE_RING (1<<0)
> #define I915_GEN_PMU_SAMPLE_PID (1<<1)
> #define I915_GEN_PMU_SAMPLE_TAG (1<<2)
> +#define I915_GEN_PMU_SAMPLE_MMIO (1<<3)
> int sample_info_flags;
> + u32 mmio_list[8];
> } gen_pmu;
>
> void (*insert_profile_cmd[I915_PROFILE_MAX])
> diff --git a/drivers/gpu/drm/i915/i915_oa_perf.c b/drivers/gpu/drm/i915/i915_oa_perf.c
> index 1cc16ef..a9d44e0 100644
> --- a/drivers/gpu/drm/i915/i915_oa_perf.c
> +++ b/drivers/gpu/drm/i915/i915_oa_perf.c
> @@ -113,8 +113,8 @@ void i915_gen_insert_cmd_ts(struct intel_ringbuffer *ringbuf, u32 ctx_id,
> struct drm_i915_gem_object *obj = dev_priv->gen_pmu.buffer.obj;
> struct i915_gen_pmu_node *entry;
> unsigned long lock_flags;
> - u32 addr = 0;
> - int ret;
> + u32 mmio_addr, addr = 0;
> + int ret, i;
>
> entry = kzalloc(sizeof(*entry), GFP_KERNEL);
> if (entry == NULL) {
> @@ -150,6 +150,7 @@ void i915_gen_insert_cmd_ts(struct intel_ringbuffer *ringbuf, u32 ctx_id,
> spin_unlock_irqrestore(&dev_priv->gen_pmu.lock, lock_flags);
>
> addr = i915_gem_obj_ggtt_offset(obj) + entry->offset;
> + mmio_addr = addr + sizeof(struct drm_i915_ts_data);
>
> if (ring->id == RCS) {
> ret = intel_ring_begin(ring, 6);
> @@ -177,6 +178,25 @@ void i915_gen_insert_cmd_ts(struct intel_ringbuffer *ringbuf, u32 ctx_id,
> intel_ring_emit(ring, 0); /* imm high, must be zero */
> intel_ring_advance(ring);
> }
> + for (i = 0; i < 8; i++) {
> + if (0 == dev_priv->gen_pmu.mmio_list[i])
> + break;
> +
> + addr = mmio_addr +
> + i * sizeof(dev_priv->gen_pmu.mmio_list[i]);
> +
> + ret = intel_ring_begin(ring, 4);
> + if (ret)
> + return;
> +
> + intel_ring_emit(ring,
> + MI_STORE_REGISTER_MEM(1) |
> + MI_SRM_LRM_GLOBAL_GTT);
> + intel_ring_emit(ring, dev_priv->gen_pmu.mmio_list[i]);
> + intel_ring_emit(ring, addr);
> + intel_ring_emit(ring, MI_NOOP);
> + intel_ring_advance(ring);
Premature optimisation, but can we store the register array with a single command?
for (i = 0; i < 8; i++) {
if (0 == dev_priv->gen_pmu.mmio_list[i])
break;
ret = intel_ring_begin(ring, 2*i + 2);
if (ret)
return;
intel_ring_emit(MI_STORE_REGISTER_MEM(i));
for (i = 0; i < 8; i++) {
if (0 == dev_priv->gen_pmu.mmio_list[i])
break;
intel_ring_emit(dev_priv->gen_pmu.mmio_list[i]);
intel_ring_emit(addr + i*4);
}
intel_ring_emit(MI_NOOP);
You should also consider ensuring that we have a command barrier between
these and 3d operations. If only we had engine->emit_flush(I915_COMMAND_BARRIER).
> +/* Some embargoed entries missing from whitelist */
> +static const struct register_whitelist {
> + uint64_t offset;
> + uint32_t size;
> + /* supported gens, 0x10 for 4, 0x30 for 4 and 5, etc. */
> + uint32_t gen_bitmask;
> +} whitelist[] = {
> + { GEN6_GT_GFX_RC6, 4, GEN_RANGE(7, 9) },
> + { GEN6_GT_GFX_RC6p, 4, GEN_RANGE(7, 9) },
> +};
> +
> +static int check_mmio_whitelist(struct drm_i915_private *dev_priv,
> + struct drm_i915_gen_pmu_attr *gen_attr)
Just what I came looking for.
> +{
> + struct register_whitelist const *entry = whitelist;
> + int i, count;
> +
> + for (count = 0; count < 8; count++) {
hardcoded value, ARRAY_SIZE(gen_attr->mmio_list)
> + if (!gen_attr->mmio_list[count])
> + break;
> +
> + for (i = 0; i < ARRAY_SIZE(whitelist); i++, entry++) {
Interesting choice of continuation in the ABI. Seems a litte forced.
Move the whitelist into the function, no one else should think of
accessing it (right?), then just use whitelist[i].
> + if (entry->offset == gen_attr->mmio_list[count] &&
> + (1 << INTEL_INFO(dev_priv->dev)->gen &
dev_priv->dev->dev_priv->info, you have to be kidding me.
INTEL_INFO(dev_priv) is the natural form.
> + entry->gen_bitmask))
> + break;
> + }
> +
> + if (i == ARRAY_SIZE(whitelist))
> + return -EINVAL;
> + }
> + return 0;
> +}
> +
> static int i915_gen_event_init(struct perf_event *event)
> {
> struct drm_i915_private *dev_priv =
> @@ -1674,6 +1740,17 @@ static int i915_gen_event_init(struct perf_event *event)
> if (gen_attr.sample_tag)
> dev_priv->gen_pmu.sample_info_flags |= I915_GEN_PMU_SAMPLE_TAG;
>
> + if (gen_attr.sample_mmio) {
> + ret = check_mmio_whitelist(dev_priv, &gen_attr);
> + if (ret)
> + return ret;
Global hw state should only be inspectable by root (unless the system
has relaxed perf permissions).
> + dev_priv->gen_pmu.sample_info_flags |=
> + I915_GEN_PMU_SAMPLE_MMIO;
> + memcpy(dev_priv->gen_pmu.mmio_list, gen_attr.mmio_list,
> + sizeof(dev_priv->gen_pmu.mmio_list));
> + }
> +
> /* To avoid the complexity of having to accurately filter
> * data and marshal to the appropriate client
> * we currently only allow exclusive access */
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index 7ab4972..65bc39d 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -81,7 +81,7 @@
>
> #define I915_OA_ATTR_SIZE_VER0 32 /* sizeof first published struct */
>
> -#define I915_GEN_PMU_ATTR_SIZE_VER0 8 /* sizeof first published struct */
> +#define I915_GEN_PMU_ATTR_SIZE_VER0 40 /* sizeof first published struct */
>
> typedef struct _drm_i915_oa_attr {
> __u32 size;
> @@ -105,7 +105,9 @@ struct drm_i915_gen_pmu_attr {
> __u32 sample_ring:1,
> sample_pid:1,
> sample_tag:1,
> - __reserved_1:29;
> + sample_mmio:1,
> + __reserved_1:28;
> + __u32 mmio_list[8];
> };
seems like having a
BUILD_BUG_ON(sizeof(struct _drm_i915_oa_attr) != I915_GEN_PMU_ATTR_SIZE_VER0) is in order.
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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