linux-kernel - RE: [PATCH v2 6/7] media: chips-media: wave5: Reduce high CPU load

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Message-ID:
 <SE1P216MB13038A70DBB710BE13294125ED64A@SE1P216MB1303.KORP216.PROD.OUTLOOK.COM>
Date: Tue, 27 May 2025 05:05:17 +0000
From: jackson.lee <jackson.lee@...psnmedia.com>
To: Nicolas Dufresne <nicolas.dufresne@...labora.com>, "mchehab@...nel.org"
	<mchehab@...nel.org>, "hverkuil-cisco@...all.nl" <hverkuil-cisco@...all.nl>,
	"sebastian.fricke@...labora.com" <sebastian.fricke@...labora.com>,
	"bob.beckett@...labora.com" <bob.beckett@...labora.com>,
	"dafna.hirschfeld@...labora.com" <dafna.hirschfeld@...labora.com>
CC: "linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, lafley.kim
	<lafley.kim@...psnmedia.com>, "b-brnich@...com" <b-brnich@...com>,
	"hverkuil@...all.nl" <hverkuil@...all.nl>, Nas Chung
	<nas.chung@...psnmedia.com>
Subject: RE: [PATCH v2 6/7] media: chips-media: wave5: Reduce high CPU load

Hi Nicolas

> -----Original Message-----
> From: Nicolas Dufresne <nicolas.dufresne@...labora.com>
> Sent: Saturday, May 24, 2025 2:43 AM
> To: jackson.lee <jackson.lee@...psnmedia.com>; mchehab@...nel.org;
> hverkuil-cisco@...all.nl; sebastian.fricke@...labora.com;
> bob.beckett@...labora.com; dafna.hirschfeld@...labora.com
> Cc: linux-media@...r.kernel.org; linux-kernel@...r.kernel.org; lafley.kim
> <lafley.kim@...psnmedia.com>; b-brnich@...com; hverkuil@...all.nl; Nas
> Chung <nas.chung@...psnmedia.com>
> Subject: Re: [PATCH v2 6/7] media: chips-media: wave5: Reduce high CPU
> load
> 
> Hi,
> 
> Le jeudi 22 mai 2025 à 16:26 +0900, Jackson.lee a écrit :
> > From: Jackson Lee <jackson.lee@...psnmedia.com>
> >
> > Since applying changes for performance improvement of decoder, there
> > was a problem related to high CPU load.
> > CPU load was more than 4 times when comparing CPU load.
> > The root cause was the device_run was called many times even if there
> > was no bitstream which should be queued.
> 
> You should squash this.
> 
> Nicolas
> 


I will also squash this to the performance patch.

Thanks
Jackson


> >
> > Signed-off-by: Jackson Lee <jackson.lee@...psnmedia.com>
> > Signed-off-by: Nas Chung <nas.chung@...psnmedia.com>
> > ---
> >  .../media/platform/chips-media/wave5/wave5-vpu-dec.c | 12
> > +++++++++---
> >  .../media/platform/chips-media/wave5/wave5-vpuapi.h  |  1 +
> >  2 files changed, 10 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/media/platform/chips-media/wave5/wave5-vpu-dec.c
> > b/drivers/media/platform/chips- media/wave5/wave5-vpu-dec.c index
> > 719c5527eb7f..421a9e1a6f15 100644
> > --- a/drivers/media/platform/chips-media/wave5/wave5-vpu-dec.c
> > +++ b/drivers/media/platform/chips-media/wave5/wave5-vpu-dec.c
> > @@ -1280,10 +1280,13 @@ static void wave5_vpu_dec_buf_queue(struct
> vb2_buffer *vb)
> >  		__func__, vb->type, vb->index, vb2_plane_size(&vbuf->vb2_buf,
> 0),
> >  		vb2_plane_size(&vbuf->vb2_buf, 1), vb2_plane_size(&vbuf-
> >vb2_buf,
> > 2));
> >
> > -	if (vb->type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE)
> > +	if (vb->type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE) {
> > +		if (inst->empty_queue)
> > +			inst->empty_queue = false;
> >  		wave5_vpu_dec_buf_queue_src(vb);
> > -	else if (vb->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE)
> > +	} else if (vb->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE) {
> >  		wave5_vpu_dec_buf_queue_dst(vb);
> > +	}
> >  }
> >
> >  static int wave5_vpu_dec_allocate_ring_buffer(struct vpu_instance
> > *inst) @@ -1474,6 +1477,7 @@ static void
> > wave5_vpu_dec_stop_streaming(struct vb2_queue *q)
> >
> >  	dev_dbg(inst->dev->dev, "%s: type: %u\n", __func__, q->type);
> >  	pm_runtime_resume_and_get(inst->dev->dev);
> > +	inst->empty_queue = false;
> >
> >  	while (check_cmd) {
> >  		struct queue_status_info q_status;
> > @@ -1592,6 +1596,7 @@ static void wave5_vpu_dec_device_run(void *priv)
> >  				inst->queuing_num == 0 &&
> >  				inst->state == VPU_INST_STATE_PIC_RUN) {
> >  			dev_dbg(inst->dev->dev, "%s: no bitstream for feeding,
> so skip ",
> > __func__);
> > +			inst->empty_queue = true;
> >  			goto finish_job_and_return;
> >  		}
> >  	}
> > @@ -1737,7 +1742,8 @@ static int wave5_vpu_dec_job_ready(void *priv)
> >  				"No capture buffer ready to decode!\n");
> >  			break;
> >  		} else if (!wave5_is_draining_or_eos(inst) &&
> > -			   !v4l2_m2m_num_src_bufs_ready(m2m_ctx)) {
> > +			   (!v4l2_m2m_num_src_bufs_ready(m2m_ctx) ||
> > +			    inst->empty_queue)) {
> >  			dev_dbg(inst->dev->dev,
> >  				"No bitstream data to decode!\n");
> >  			break;
> > diff --git a/drivers/media/platform/chips-media/wave5/wave5-vpuapi.h
> > b/drivers/media/platform/chips-media/wave5/wave5-
> > vpuapi.h
> > index fd0aef0bac4e..f2596af08cdf 100644
> > --- a/drivers/media/platform/chips-media/wave5/wave5-vpuapi.h
> > +++ b/drivers/media/platform/chips-media/wave5/wave5-vpuapi.h
> > @@ -821,6 +821,7 @@ struct vpu_instance {
> >  	bool retry; /* retry to feed bitstream if failure reason is
> WAVE5_SYSERR_QUEUEING_FAIL*/
> >  	int queuing_num; /* check if there is input buffer or not */
> >  	struct mutex feed_lock; /* lock for feeding bitstream buffers */
> > +	bool empty_queue;
> >  	struct vpu_buf bitstream_vbuf;
> >  	dma_addr_t last_rd_ptr;
> >  	size_t remaining_consumed_bytes;