[PATCH v3] drm/xe/guc: Configure TLB timeout based on CT buffer size
Nirmoy Das
nirmoy.das at intel.com
Fri Jun 28 08:58:00 UTC 2024
Hi Michal,
Thanks a lot for taking time to review this so nicely!
On 6/27/2024 10:40 PM, Michal Wajdeczko wrote:
>
> On 26.06.2024 17:01, Nirmoy Das wrote:
>> GuC TLB invalidation depends on GuC to process the request from the CT
>> queue and then the real time to invalidate TLB. Add a function to return
>> overestimated possible time a TLB inval H2G might take which can be used
>> as timeout value for TLB invalidation wait time.
>>
>> v3: Pass CT to xe_guc_ct_queue_proc_time_jiffies() (Michal)
>> Add tlb_timeout_jiffies() that replaces TLB_TIMEOUT(Michal)
>> v2: Address reviews from Michal.
>>
>> Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/1622
>> Cc: Matthew Brost <matthew.brost at intel.com>
>> Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
>> Suggested-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
>> Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
>> ---
>> drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c | 30 +++++++++++++++------
>> drivers/gpu/drm/xe/xe_guc_ct.c | 16 +++++++++++
>> drivers/gpu/drm/xe/xe_guc_ct.h | 2 ++
>> 3 files changed, 40 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c b/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
>> index e1f1ccb01143..d509b72a6d89 100644
>> --- a/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
>> +++ b/drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c
>> @@ -17,7 +17,22 @@
>> #include "xe_trace.h"
>> #include "regs/xe_guc_regs.h"
>>
>> -#define TLB_TIMEOUT (HZ / 4)
>> +/**
> downgrade to normal comment
Will do that.
>
>> + * TLB inval depends on pending commands in the CT queue and then the real
>> + * invalidation time. Double up the time to process full CT queue
>> + * just to be on the safe side.
>> + */
>> +static long tlb_timeout_jiffies(struct xe_gt *gt)
>> +{
>> + /* this reflects what HW/GuC needs to process TLB inv request */
>> + const long hw_tlb_timeout = HZ / 4;
>> +
>> + /* this estimates actual delay caused by the CTB transport */
>> + long delay = xe_guc_ct_queue_proc_time_jiffies(>->uc.guc.ct);
>> +
>> + return hw_tlb_timeout + 2 * delay;
>> +}
>> +
>>
>> static void xe_gt_tlb_fence_timeout(struct work_struct *work)
>> {
>> @@ -32,7 +47,7 @@ static void xe_gt_tlb_fence_timeout(struct work_struct *work)
>> s64 since_inval_ms = ktime_ms_delta(ktime_get(),
>> fence->invalidation_time);
>>
>> - if (msecs_to_jiffies(since_inval_ms) < TLB_TIMEOUT)
>> + if (msecs_to_jiffies(since_inval_ms) < tlb_timeout_jiffies(gt))
>> break;
>>
>> trace_xe_gt_tlb_invalidation_fence_timeout(xe, fence);
>> @@ -47,7 +62,7 @@ static void xe_gt_tlb_fence_timeout(struct work_struct *work)
>> if (!list_empty(>->tlb_invalidation.pending_fences))
>> queue_delayed_work(system_wq,
>> >->tlb_invalidation.fence_tdr,
>> - TLB_TIMEOUT);
>> + tlb_timeout_jiffies(gt));
>> spin_unlock_irq(>->tlb_invalidation.pending_lock);
>> }
>>
>> @@ -183,7 +198,7 @@ static int send_tlb_invalidation(struct xe_guc *guc,
>> if (list_is_singular(>->tlb_invalidation.pending_fences))
>> queue_delayed_work(system_wq,
>> >->tlb_invalidation.fence_tdr,
>> - TLB_TIMEOUT);
>> + tlb_timeout_jiffies(gt));
>> }
>> spin_unlock_irq(>->tlb_invalidation.pending_lock);
>> } else if (ret < 0 && fence) {
>> @@ -390,8 +405,7 @@ int xe_gt_tlb_invalidation_vma(struct xe_gt *gt,
>> * @gt: graphics tile
>> * @seqno: seqno to wait which was returned from xe_gt_tlb_invalidation
>> *
>> - * Wait for 200ms for a TLB invalidation to complete, in practice we always
>> - * should receive the TLB invalidation within 200ms.
>> + * Wait for tlb_timeout_jiffies() for a TLB invalidation to complete.
>> *
>> * Return: 0 on success, -ETIME on TLB invalidation timeout
>> */
>> @@ -410,7 +424,7 @@ int xe_gt_tlb_invalidation_wait(struct xe_gt *gt, int seqno)
>> */
>> ret = wait_event_timeout(guc->ct.wq,
>> tlb_invalidation_seqno_past(gt, seqno),
>> - TLB_TIMEOUT);
>> + tlb_timeout_jiffies(gt));
>> if (!ret) {
>> struct drm_printer p = xe_gt_err_printer(gt);
>>
>> @@ -486,7 +500,7 @@ int xe_guc_tlb_invalidation_done_handler(struct xe_guc *guc, u32 *msg, u32 len)
>> if (!list_empty(>->tlb_invalidation.pending_fences))
>> mod_delayed_work(system_wq,
>> >->tlb_invalidation.fence_tdr,
>> - TLB_TIMEOUT);
>> + tlb_timeout_jiffies(gt));
>> else
>> cancel_delayed_work(>->tlb_invalidation.fence_tdr);
>>
>> diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
>> index 873d1bcbedd7..df95b0e878ad 100644
>> --- a/drivers/gpu/drm/xe/xe_guc_ct.c
>> +++ b/drivers/gpu/drm/xe/xe_guc_ct.c
>> @@ -112,6 +112,22 @@ ct_to_xe(struct xe_guc_ct *ct)
>> #define CTB_G2H_BUFFER_SIZE (4 * CTB_H2G_BUFFER_SIZE)
>> #define G2H_ROOM_BUFFER_SIZE (CTB_G2H_BUFFER_SIZE / 4)
>>
>> +/**
>> + * xe_guc_ct_queue_proc_time_jiffies - Return maximum time to process a full
>> + * CT command queue
>> + * @ct: the &xe_guc_ct. Unused at this moment but will be used in the future.
>> + *
>> + * Observation is that A 4KiB buffer full of commands takes a little over a
> s/A/a
Wish checkpatch could catch that.
>
>> + * second to process. Use that to calculate maximum time to process a full CT
>> + * command queue.
>> + *
>> + * Return: Maximum time to process a full CT queue in jiffies.
>> + */
>> +long xe_guc_ct_queue_proc_time_jiffies(struct xe_guc_ct *ct)
>> +{
>> + return (CTB_H2G_BUFFER_SIZE * HZ) / SZ_4K;
> maybe make sure CTB is in 4K blocks
>
> BUILD_BUG_ON(!IS_ALIGNED(CTB_H2G_BUFFER_SIZE, SZ_4));
>
> and to better reflect the time logic:
>
> return (CTB_H2G_BUFFER_SIZE / SZ_4K) * HZ;
Sounds good. Will add that.
>
>> +}
>> +
>> static size_t guc_ct_size(void)
>> {
>> return 2 * CTB_DESC_SIZE + CTB_H2G_BUFFER_SIZE +
>> diff --git a/drivers/gpu/drm/xe/xe_guc_ct.h b/drivers/gpu/drm/xe/xe_guc_ct.h
>> index 105bb8e99a8d..190202fce2d0 100644
>> --- a/drivers/gpu/drm/xe/xe_guc_ct.h
>> +++ b/drivers/gpu/drm/xe/xe_guc_ct.h
>> @@ -64,4 +64,6 @@ xe_guc_ct_send_block_no_fail(struct xe_guc_ct *ct, const u32 *action, u32 len)
>> return xe_guc_ct_send_recv_no_fail(ct, action, len, NULL);
>> }
>>
>> +long xe_guc_ct_queue_proc_time_jiffies(struct xe_guc_ct *ct);
>> +
>> #endif
> with that,
>
> Reviewed-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
Thanks. I will resend with above suggestions.
Nirmoy
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