[PATCH 1/2] drm/xe: Add sent and recv counters for tlb invalidations
Nirmoy Das
nirmoy.das at linux.intel.com
Wed Jul 24 09:20:19 UTC 2024
On 7/23/2024 6:23 PM, Matthew Brost wrote:
> On Tue, Jul 23, 2024 at 03:07:05PM +0200, Nirmoy Das wrote:
>> On 7/23/2024 2:22 PM, Michal Wajdeczko wrote:
>>> On 23.07.2024 13:16, Nirmoy Das wrote:
>>>> Add counters for TLB invalidation sent, receive requests which
>>>> then could be query as sysfs files from userspace.
>>> s/sysfs/debugfs ?
>>
>> I will fix it.
>>
> I think this debugfs then I think we certainly need to hide this
> implementation behind a Kconfig option as atomics have a non-zero
> execution cost.
>
> I'm thinking a generic DRM_XE_DEBUG_STATS or something.
>
> Then also with that, build generic stats layer which other code calls
> into and stats object which encapsulates all the stats.
>
> Fine with only having TLB invalidations to start but having the
> infrastructure to add more stats over time would be good.
Ok, I will give it a try and improve it with further suggestions.
Thanks,
Nirmoy
>
> Matt
>
>>>> Cc: Matthew Brost <matthew.brost at intel.com>
>>>> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
>>>> Cc: Sai Gowtham Ch <sai.gowtham.ch at intel.com>
>>>> Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
>>>> ---
>>>> drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c | 37 +++++++++++++++------
>>>> drivers/gpu/drm/xe/xe_gt_types.h | 4 +++
>>>> 2 files changed, 30 insertions(+), 11 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c b/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
>>>> index 481d83d07367..f84717c1aafa 100644
>>>> --- a/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
>>>> +++ b/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
>>>> @@ -37,8 +37,11 @@ static long tlb_timeout_jiffies(struct xe_gt *gt)
>>>> }
>>>> static void
>>>> -__invalidation_fence_signal(struct xe_device *xe, struct xe_gt_tlb_invalidation_fence *fence)
>>>> +__invalidation_fence_signal(struct xe_gt *gt,
>>>> + struct xe_gt_tlb_invalidation_fence *fence,
>>>> + bool failed)
>>>> {
>>>> + struct xe_device *xe = gt_to_xe(gt);
>>>> bool stack = test_bit(FENCE_STACK_BIT, &fence->base.flags);
>>>> trace_xe_gt_tlb_invalidation_fence_signal(xe, fence);
>>>> @@ -46,13 +49,19 @@ __invalidation_fence_signal(struct xe_device *xe, struct xe_gt_tlb_invalidation_
>>>> dma_fence_signal(&fence->base);
>>>> if (!stack)
>>>> dma_fence_put(&fence->base);
>>>> +
>>>> + /* Only increment the counter when tlb inval is done successfully */
>>>> + if (!failed)
>>>> + atomic64_inc(>->tlb_invalidation.received_count);
>>>> }
>>>> static void
>>>> -invalidation_fence_signal(struct xe_device *xe, struct xe_gt_tlb_invalidation_fence *fence)
>>>> +invalidation_fence_signal(struct xe_gt *gt,
>>>> + struct xe_gt_tlb_invalidation_fence *fence,
>>>> + bool failed)
>>>> {
>>>> list_del(&fence->link);
>>>> - __invalidation_fence_signal(xe, fence);
>>>> + __invalidation_fence_signal(gt, fence, failed);
>>>> }
>>>> static void xe_gt_tlb_fence_timeout(struct work_struct *work)
>>>> @@ -76,7 +85,7 @@ static void xe_gt_tlb_fence_timeout(struct work_struct *work)
>>>> fence->seqno, gt->tlb_invalidation.seqno_recv);
>>>> fence->base.error = -ETIME;
>>>> - invalidation_fence_signal(xe, fence);
>>>> + invalidation_fence_signal(gt, fence, true);
>>>> }
>>>> if (!list_empty(>->tlb_invalidation.pending_fences))
>>>> queue_delayed_work(system_wq,
>>>> @@ -102,6 +111,8 @@ int xe_gt_tlb_invalidation_init(struct xe_gt *gt)
>>>> spin_lock_init(>->tlb_invalidation.lock);
>>>> INIT_DELAYED_WORK(>->tlb_invalidation.fence_tdr,
>>>> xe_gt_tlb_fence_timeout);
>>>> + atomic64_set(>->tlb_invalidation.sent_count, 0);
>>>> + atomic64_set(>->tlb_invalidation.received_count, 0);
>>>> return 0;
>>>> }
>>>> @@ -140,7 +151,9 @@ void xe_gt_tlb_invalidation_reset(struct xe_gt *gt)
>>>> list_for_each_entry_safe(fence, next,
>>>> >->tlb_invalidation.pending_fences, link)
>>>> - invalidation_fence_signal(gt_to_xe(gt), fence);
>>>> + invalidation_fence_signal(gt, fence, false);
>>>> + atomic64_set(>->tlb_invalidation.sent_count, 0);
>>>> + atomic64_set(>->tlb_invalidation.received_count, 0);
>>> hmm, any TLB invalidation timeouts/errors, which would make
>>> received_count != sent_count, should trigger a GT reset, which in turn
>>> will reset those counters, so under which condition you expect those two
>>> stats being not equal?
>> We tolerate GGTT tlb inval timeouts without needed to do a GT reset,
>> probably we shouldn't? If not then, I agree that we can have
>>
>> a total sent counter and another for inflight counter.
>>
>>
>>> is it just during the waiting for some ack?
>>>
>>> maybe better/cleaner option would be to track/display number of TLB
>>> invalidation requests in flight ?
>>
>> Request from Sai was about having total tlb inval sent counter and I think
>> inflight would be a bonus and should be useful for debugging.
>>
>>
>> Regards,
>>
>> Nirmoy
>>
>>>> spin_unlock_irq(>->tlb_invalidation.pending_lock);
>>>> mutex_unlock(>->uc.guc.ct.lock);
>>>> }
>>>> @@ -182,7 +195,7 @@ static int send_tlb_invalidation(struct xe_guc *guc,
>>>> action[1] = seqno;
>>>> ret = xe_guc_ct_send_locked(&guc->ct, action, len,
>>>> G2H_LEN_DW_TLB_INVALIDATE, 1);
>>>> - if (!ret && fence) {
>>>> + if (!ret) {
>>>> spin_lock_irq(>->tlb_invalidation.pending_lock);
>>>> /*
>>>> * We haven't actually published the TLB fence as per
>>>> @@ -191,7 +204,7 @@ static int send_tlb_invalidation(struct xe_guc *guc,
>>>> * we can just go ahead and signal the fence here.
>>>> */
>>>> if (tlb_invalidation_seqno_past(gt, seqno)) {
>>>> - __invalidation_fence_signal(xe, fence);
>>>> + __invalidation_fence_signal(gt, fence, false);
>>>> } else {
>>>> fence->invalidation_time = ktime_get();
>>>> list_add_tail(&fence->link,
>>>> @@ -203,14 +216,16 @@ static int send_tlb_invalidation(struct xe_guc *guc,
>>>> tlb_timeout_jiffies(gt));
>>>> }
>>>> spin_unlock_irq(>->tlb_invalidation.pending_lock);
>>>> - } else if (ret < 0 && fence) {
>>>> - __invalidation_fence_signal(xe, fence);
>>>> + } else if (ret < 0) {
>>>> + __invalidation_fence_signal(gt, fence, true);
>>>> }
>>>> if (!ret) {
>>>> gt->tlb_invalidation.seqno = (gt->tlb_invalidation.seqno + 1) %
>>>> TLB_INVALIDATION_SEQNO_MAX;
>>>> if (!gt->tlb_invalidation.seqno)
>>>> gt->tlb_invalidation.seqno = 1;
>>>> +
>>>> + atomic64_inc(>->tlb_invalidation.sent_count);
>>>> }
>>>> mutex_unlock(&guc->ct.lock);
>>>> @@ -321,7 +336,7 @@ int xe_gt_tlb_invalidation_range(struct xe_gt *gt,
>>>> /* Execlists not supported */
>>>> if (gt_to_xe(gt)->info.force_execlist) {
>>>> - __invalidation_fence_signal(xe, fence);
>>>> + __invalidation_fence_signal(gt, fence, true);
>>>> return 0;
>>>> }
>>>> @@ -455,7 +470,7 @@ int xe_guc_tlb_invalidation_done_handler(struct xe_guc *guc, u32 *msg, u32 len)
>>>> if (!tlb_invalidation_seqno_past(gt, fence->seqno))
>>>> break;
>>>> - invalidation_fence_signal(xe, fence);
>>>> + invalidation_fence_signal(gt, fence, false);
>>>> }
>>>> if (!list_empty(>->tlb_invalidation.pending_fences))
>>>> diff --git a/drivers/gpu/drm/xe/xe_gt_types.h b/drivers/gpu/drm/xe/xe_gt_types.h
>>>> index ef68c4a92972..130d9f5cb5c2 100644
>>>> --- a/drivers/gpu/drm/xe/xe_gt_types.h
>>>> +++ b/drivers/gpu/drm/xe/xe_gt_types.h
>>>> @@ -199,6 +199,10 @@ struct xe_gt {
>>>> struct delayed_work fence_tdr;
>>>> /** @tlb_invalidation.lock: protects TLB invalidation fences */
>>>> spinlock_t lock;
>>>> + /** @tlb_invalidation.sent_count: counter for sent TLB inval requests */
>>>> + atomic64_t sent_count;
>>>> + /** @tlb_invalidation.received_count: counter for received TLB inval requestes */
>>>> + atomic64_t received_count;
>>>> } tlb_invalidation;
>>>> /**
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