Add a new event tracepoint: gpu_cache_flush to be emitted after a GPU cache flush completes, with duration and return status arguments.
This allows debugging the duration a flush takes irrespective of initial function entry lock contention, and communicates information about whether the flush timed out or errored out in other ways, and which caches were flushed. Signed-off-by: Nicolas Frattaroli <[email protected]> --- drivers/gpu/drm/panthor/panthor_gpu.c | 26 +++++++++++++++++++++- drivers/gpu/drm/panthor/panthor_trace.h | 38 +++++++++++++++++++++++++++++++++ 2 files changed, 63 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/panthor/panthor_gpu.c b/drivers/gpu/drm/panthor/panthor_gpu.c index c013d6bf9a59..7088371c6d64 100644 --- a/drivers/gpu/drm/panthor/panthor_gpu.c +++ b/drivers/gpu/drm/panthor/panthor_gpu.c @@ -317,6 +317,21 @@ int panthor_gpu_l2_power_on(struct panthor_device *ptdev) return panthor_gpu_power_on(ptdev, L2, 1, 20000); } +static inline void panthor_gpu_emit_flush_caches_tp(struct panthor_device *ptdev, + u64 start, u32 l2, u32 lsc, + u32 other, int ret) +{ + u32 duration; + + if (!tracepoint_enabled(gpu_cache_flush) || !start) + return; + + if (check_sub_overflow(ktime_get_ns(), start, &duration)) + duration = U32_MAX; + + trace_gpu_cache_flush(ptdev->base.dev, l2, lsc, other, duration, ret); +} + /** * panthor_gpu_flush_caches() - Flush caches * @ptdev: Device. @@ -331,12 +346,17 @@ int panthor_gpu_flush_caches(struct panthor_device *ptdev, { struct panthor_gpu *gpu = ptdev->gpu; unsigned long flags; + u64 start = 0; int ret = 0; /* Serialize cache flush operations. */ guard(mutex)(&ptdev->gpu->cache_flush_lock); spin_lock_irqsave(&ptdev->gpu->reqs_lock, flags); + + if (tracepoint_enabled(gpu_cache_flush)) + start = ktime_get_ns(); + if (!(ptdev->gpu->pending_reqs & GPU_IRQ_CLEAN_CACHES_COMPLETED)) { ptdev->gpu->pending_reqs |= GPU_IRQ_CLEAN_CACHES_COMPLETED; gpu_write(gpu->iomem, GPU_CMD, GPU_FLUSH_CACHES(l2, lsc, other)); @@ -345,8 +365,10 @@ int panthor_gpu_flush_caches(struct panthor_device *ptdev, } spin_unlock_irqrestore(&ptdev->gpu->reqs_lock, flags); - if (ret) + if (ret) { + panthor_gpu_emit_flush_caches_tp(ptdev, start, l2, lsc, other, ret); return ret; + } if (!wait_event_timeout(ptdev->gpu->reqs_acked, !(ptdev->gpu->pending_reqs & GPU_IRQ_CLEAN_CACHES_COMPLETED), @@ -360,6 +382,8 @@ int panthor_gpu_flush_caches(struct panthor_device *ptdev, spin_unlock_irqrestore(&ptdev->gpu->reqs_lock, flags); } + panthor_gpu_emit_flush_caches_tp(ptdev, start, l2, lsc, other, ret); + if (ret) { panthor_device_schedule_reset(ptdev); drm_err(&ptdev->base, "Flush caches timeout"); diff --git a/drivers/gpu/drm/panthor/panthor_trace.h b/drivers/gpu/drm/panthor/panthor_trace.h index 6ffeb4fe6599..bd8652549ab4 100644 --- a/drivers/gpu/drm/panthor/panthor_trace.h +++ b/drivers/gpu/drm/panthor/panthor_trace.h @@ -76,6 +76,44 @@ TRACE_EVENT(gpu_job_irq, __entry->events, __entry->duration_ns) ); +/** + * gpu_cache_flush - emitted after cache flush completes + * @dev: pointer to the &struct device, for printing the device name + * @l2: "l2" flush flags + * @lsc: "lsc" flush flags + * @other: "other" flush flags + * @duration_ns: how long the cache flush operation took, in nanoseconds + * @ret: return status, 0 == success, negative errno on error + * + * Begins measuring after any initial lock contention around the locks needed + * for flushing caches, but before the actual cache flush is requested. Stops + * measuring and is emitted after flush operation is over. + */ +TRACE_EVENT(gpu_cache_flush, + TP_PROTO(const struct device *dev, u32 l2, u32 lsc, u32 other, + u32 duration_ns, int ret), + TP_ARGS(dev, l2, lsc, other, duration_ns, ret), + TP_STRUCT__entry( + __string(dev_name, dev_name(dev)) + __field(u32, l2) + __field(u32, lsc) + __field(u32, other) + __field(u32, duration_ns) + __field(int, ret) + ), + TP_fast_assign( + __assign_str(dev_name); + __entry->l2 = l2; + __entry->lsc = lsc; + __entry->other = other; + __entry->duration_ns = duration_ns; + __entry->ret = ret; + ), + TP_printk("%s: l2=0x%x lsc=0x%x other=0x%x duration_ns=%u ret=%d", + __get_str(dev_name), __entry->l2, __entry->lsc, + __entry->other, __entry->duration_ns, __entry->ret) +); + #endif /* __PANTHOR_TRACE_H__ */ #undef TRACE_INCLUDE_PATH -- 2.55.0
