[PATCH v2 8/9] media: Add HW run/done trace events
From: Detlev Casanova <detlev.casanova@collabora.com>
Date: 2026-06-10 14:34:42
Also in:
linux-arm-kernel, linux-media, linux-rockchip, lkml
Subsystem:
media input infrastructure (v4l/dvb), the rest, tracing · Maintainers:
Mauro Carvalho Chehab, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
The events can be fired by drivers when the hardware is run and when it is done. That can be used by userspace tracers to see HW performance and usage. The hw_done event allows setting the number of clock cycles the HW needed to do the work, to help tools evaluate performances. Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com> --- drivers/media/v4l2-core/v4l2-trace.c | 3 +++ include/trace/events/v4l2.h | 40 ++++++++++++++++++++++++++++++++++++ 2 files changed, 43 insertions(+)
diff --git a/drivers/media/v4l2-core/v4l2-trace.c b/drivers/media/v4l2-core/v4l2-trace.c
index 183d5ecb49c5..59cf6f8807ac 100644
--- a/drivers/media/v4l2-core/v4l2-trace.c
+++ b/drivers/media/v4l2-core/v4l2-trace.c@@ -12,6 +12,9 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(vb2_v4l2_buf_queue); EXPORT_TRACEPOINT_SYMBOL_GPL(vb2_v4l2_dqbuf); EXPORT_TRACEPOINT_SYMBOL_GPL(vb2_v4l2_qbuf); +EXPORT_TRACEPOINT_SYMBOL_GPL(v4l2_hw_run); +EXPORT_TRACEPOINT_SYMBOL_GPL(v4l2_hw_done); + /* Export AV1 controls */ EXPORT_TRACEPOINT_SYMBOL_GPL(v4l2_ctrl_av1_sequence); EXPORT_TRACEPOINT_SYMBOL_GPL(v4l2_ctrl_av1_frame);
diff --git a/include/trace/events/v4l2.h b/include/trace/events/v4l2.h
index e5b80aeecc30..6f1bbb085cb0 100644
--- a/include/trace/events/v4l2.h
+++ b/include/trace/events/v4l2.h@@ -299,6 +299,46 @@ DEFINE_EVENT(v4l2_stream_class, v4l2_streamoff, TP_ARGS(tgid, fd) ); + +/* Events for hardware run/done. + * + * These events will be fired respectively when the hardware is run (v4l2_hw_run) and done + * (v4l2_hw_done). + * As for other events, tgid and fd are used to identify the process that opened the video device. + * + * The v4l2_hw_done event also includes the number of hardware cycles taken by the hardware to + * process the command. + */ +DEFINE_EVENT(v4l2_stream_class, v4l2_hw_run, + TP_PROTO(u32 tgid, u32 fd), + TP_ARGS(tgid, fd) +); + +DECLARE_EVENT_CLASS(v4l2_hw_done_class, + TP_PROTO(u32 tgid, u32 fd, u32 hw_cycles), + TP_ARGS(tgid, fd, hw_cycles), + + TP_STRUCT__entry( + __field(u32, tgid) + __field(u32, fd) + __field(u32, hw_cycles) + ), + + TP_fast_assign( + __entry->tgid = tgid; + __entry->fd = fd; + __entry->hw_cycles = hw_cycles; + ), + + TP_printk("tgid = %u, fd = %u, hw_cycles = %u", + __entry->tgid, __entry->fd, __entry->hw_cycles) +); + +DEFINE_EVENT(v4l2_hw_done_class, v4l2_hw_done, + TP_PROTO(u32 tgid, u32 fd, u32 hw_cycles), + TP_ARGS(tgid, fd, hw_cycles) +); + #endif /* if !defined(_TRACE_V4L2_H) || defined(TRACE_HEADER_MULTI_READ) */ /* This part must be outside protection */
--
2.54.0