Re: [PATCH v2 6/9] drm/xe/multi_queue: Capture queue run times for active queues

[Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>]

On Fri, May 01, 2026 at 05:53:39PM -0700, Umesh Nerlige Ramappa wrote:
>If a queue is currently active on the CS, query the QUEUE TIMESTAMP
>register to get an up to date value of the runtime. To do so, ensure
>that the primary queue is active and then check if the secondary queue
>is executing on the CS.
>
>Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
>---
>v2:
>- Move trace to a separate patch (Stuart)
>- Refactor multi queue timestamp logic (Matt/Niranjana)
>---
> drivers/gpu/drm/xe/regs/xe_engine_regs.h |   4 +
> drivers/gpu/drm/xe/xe_lrc.c              | 115 +++++++++++++++++++----
> 2 files changed, 99 insertions(+), 20 deletions(-)
>
>diff --git a/drivers/gpu/drm/xe/regs/xe_engine_regs.h b/drivers/gpu/drm/xe/regs/xe_engine_regs.h
>index 1b4a7e9a703d..af6af6f3f5e8 100644
>--- a/drivers/gpu/drm/xe/regs/xe_engine_regs.h
>+++ b/drivers/gpu/drm/xe/regs/xe_engine_regs.h
>@@ -170,6 +170,10 @@
> #define   GFX_MSIX_INTERRUPT_ENABLE		REG_BIT(13)
>
> #define RING_CSMQDEBUG(base)			XE_REG((base) + 0x2b0)
>+#define   CURRENT_ACTIVE_QUEUE_ID_MASK		REG_GENMASK(7, 0)
>+
>+#define RING_QUEUE_TIMESTAMP(base)		XE_REG((base) + 0x4c0)
>+#define RING_QUEUE_TIMESTAMP_UDW(base)		XE_REG((base) + 0x4c0 + 4)
>
> #define RING_TIMESTAMP(base)			XE_REG((base) + 0x358)
>
>diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c
>index 92419e5058fd..023202be5d52 100644
>--- a/drivers/gpu/drm/xe/xe_lrc.c
>+++ b/drivers/gpu/drm/xe/xe_lrc.c
>@@ -21,6 +21,7 @@
> #include "xe_configfs.h"
> #include "xe_device.h"
> #include "xe_drm_client.h"
>+#include "xe_exec_queue.h"
> #include "xe_exec_queue_types.h"
> #include "xe_gt.h"
> #include "xe_gt_clock.h"
>@@ -2655,17 +2656,65 @@ static int get_ctx_timestamp(struct xe_lrc *lrc, u32 engine_id, u64 *reg_ctx_ts)
> 	return 0;
> }
>
>-/**
>- * xe_lrc_timestamp() - Current ctx timestamp
>- * @lrc: Pointer to the lrc.
>- *
>- * Return latest ctx timestamp. With support for active contexts, the
>- * calculation may be slightly racy, so follow a read-again logic to ensure that
>- * the context is still active before returning the right timestamp.
>- *
>- * Returns: New ctx timestamp value
>- */
>-u64 xe_lrc_timestamp(struct xe_lrc *lrc)
>+static u64 get_queue_timestamp(struct xe_hw_engine *hwe)
>+{
>+	return xe_mmio_read64_2x32(&hwe->gt->mmio,
>+				   RING_QUEUE_TIMESTAMP(hwe->mmio_base));
>+}
>+
>+static u32 get_queue_id(struct xe_hw_engine *hwe)
>+{

NIT...may be rename it as get_multi_queue_active_queue()?

>+	u32 val = xe_mmio_read32(&hwe->gt->mmio,
>+				 RING_CSMQDEBUG(hwe->mmio_base));
>+
>+	return REG_FIELD_GET(CURRENT_ACTIVE_QUEUE_ID_MASK, val);
>+}
>+
>+static bool context_active(struct xe_lrc *lrc)
>+{
>+	return xe_lrc_ctx_timestamp(lrc) == CONTEXT_ACTIVE;
>+}
>+
>+static u64 xe_lrc_multi_queue_timestamp(struct xe_lrc *lrc)
>+{
>+	struct xe_lrc *primary_lrc = lrc->multi_queue.primary_lrc;
>+	struct xe_hw_engine *hwe;
>+	u64 reg_queue_ts = lrc->queue_timestamp;
>+
>+	if (IS_SRIOV_VF(lrc_to_xe(lrc)))
>+		return xe_lrc_queue_timestamp(lrc);
>+
>+	if (!primary_lrc || !context_active(primary_lrc))
>+		return xe_lrc_queue_timestamp(lrc);

May be print a warning if primary_lrc is not set?

>+
>+	/* WA BB populates engine id in PPHWSP of primary context only */
>+	hwe = engine_id_to_hwe(primary_lrc->gt, xe_lrc_engine_id(primary_lrc));
>+	if (!hwe)
>+		return xe_lrc_queue_timestamp(lrc);
>+
>+	if (get_queue_id(hwe) != lrc->multi_queue.pos)
>+		return xe_lrc_queue_timestamp(lrc);
>+
>+	/* queue is active, so store the queue timestamp register */
>+	reg_queue_ts = get_queue_timestamp(hwe);
>+
>+	/* double check queue and primary queue are both still active */
>+	if (get_queue_id(hwe) != lrc->multi_queue.pos ||
>+	    !context_active(primary_lrc))
>+		return xe_lrc_queue_timestamp(lrc);
>+
>+	return reg_queue_ts;
>+}
>+
>+static u64 xe_lrc_update_multi_queue_timestamp(struct xe_lrc *lrc, u64 *old_ts)
>+{
>+	*old_ts = lrc->queue_timestamp;
>+	lrc->queue_timestamp = xe_lrc_multi_queue_timestamp(lrc);

Same here, add a warning message if lrc is not multi-queue?

>+
>+	return lrc->queue_timestamp;
>+}
>+
>+static u64 xe_lrc_single_queue_timestamp(struct xe_lrc *lrc)
> {

Hmm...NIT...we never used the word 'single_queue' so far to refer to
non-multi-queue case. May be rename it to xe_lrc_ctx_timestamp()
or something?

Also, may be update this funcion to make use the newly added
context_active() function?

Niranjana

> 	u64 lrc_ts, reg_ts, new_ts = lrc->ctx_timestamp;
> 	u32 engine_id;
>@@ -2697,24 +2746,50 @@ u64 xe_lrc_timestamp(struct xe_lrc *lrc)
> 	return new_ts;
> }
>
>+static u64 xe_lrc_update_ctx_timestamp(struct xe_lrc *lrc, u64 *old_ts)
>+{
>+	*old_ts = lrc->ctx_timestamp;
>+	lrc->ctx_timestamp = xe_lrc_single_queue_timestamp(lrc);
>+
>+	trace_xe_lrc_update_timestamp(lrc, *old_ts);
>+
>+	return lrc->ctx_timestamp;
>+}
>+
> /**
>- * xe_lrc_update_timestamp() - Update ctx timestamp
>+ * xe_lrc_timestamp() - Current lrc timestamp
>+ * @lrc: Pointer to the lrc.
>+ *
>+ * Return latest lrc timestamp. With support for active contexts/queues, the
>+ * calculation may be slightly racy, so follow a read-again logic to ensure that
>+ * the context/queue is still active before returning the right timestamp.
>+ *
>+ * Returns: New lrc timestamp value
>+ */
>+u64 xe_lrc_timestamp(struct xe_lrc *lrc)
>+{
>+	if (xe_lrc_is_multi_queue(lrc))
>+		return xe_lrc_multi_queue_timestamp(lrc);
>+	else
>+		return xe_lrc_single_queue_timestamp(lrc);
>+}
>+
>+/**
>+ * xe_lrc_update_timestamp() - Update lrc timestamp
>  * @lrc: Pointer to the lrc.
>  * @old_ts: Old timestamp value
>  *
>- * Populate @old_ts current saved ctx timestamp, read new ctx timestamp and
>+ * Populate @old_ts with current saved lrc timestamp, read new lrc timestamp and
>  * update saved value.
>  *
>- * Returns: New ctx timestamp value
>+ * Returns: New lrc timestamp value
>  */
> u64 xe_lrc_update_timestamp(struct xe_lrc *lrc, u64 *old_ts)
> {
>-	*old_ts = lrc->ctx_timestamp;
>-	lrc->ctx_timestamp = xe_lrc_timestamp(lrc);
>-
>-	trace_xe_lrc_update_timestamp(lrc, *old_ts);
>-
>-	return lrc->ctx_timestamp;
>+	if (xe_lrc_is_multi_queue(lrc))
>+		return xe_lrc_update_multi_queue_timestamp(lrc, old_ts);
>+	else
>+		return xe_lrc_update_ctx_timestamp(lrc, old_ts);
> }
>
> /**
>-- 
>2.43.0
>