[libcamera-devel,v10,07/19] libcamera: pipeline: rkisp1: Don't rely on bufferCount
diff mbox series

Message ID 20221228223003.2265712-8-paul.elder@ideasonboard.com
State New
Headers show
Series
  • lc-compliance: Add test to queue more requests than hardware depth
Related show

Commit Message

Paul Elder Dec. 28, 2022, 10:29 p.m. UTC 
From: Nícolas F. R. A. Prado <nfraprado@collabora.com>

Currently the rkisp1 pipeline handler relies on bufferCount to decide on
the number of parameter and statistics buffers to allocate internally
and for the number of V4L2 buffer slots to reserve. Instead, the number
of internal buffers should be the minimum required by the pipeline to
keep the requests flowing, in order to avoid wasting memory, while the
number of V4L2 buffer slots should be greater than the expected number
of requests queued by the application, in order to avoid thrashing
dmabuf mappings, which would degrade performance.

Stop relying on bufferCount for these numbers and instead set them to
appropriate, and independent, constants.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

---
Changes in v9:
- rebased

Changes in v8:
- New
---
 src/libcamera/pipeline/rkisp1/rkisp1.cpp      | 19 ++++++++++++-------
 src/libcamera/pipeline/rkisp1/rkisp1_path.cpp |  3 +--
 src/libcamera/pipeline/rkisp1/rkisp1_path.h   |  2 ++
 3 files changed, 15 insertions(+), 9 deletions(-)

Patch
diff mbox series 

diff --git a/src/libcamera/pipeline/rkisp1/rkisp1.cpp b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
index 5994b974..27d70c6e 100644
--- a/src/libcamera/pipeline/rkisp1/rkisp1.cpp
+++ b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
@@ -200,6 +200,16 @@  private:
 	Camera *activeCamera_;
 
 	const MediaPad *ispSink_;
+
+	/*
+	 * This many internal buffers (or rather parameter and statistics buffer
+	 * pairs) ensures that the pipeline runs smoothly, without frame drops.
+	 * This number considers:
+	 * - three buffers queued to the driver, which is also the minimum
+	 *   required to start streaming
+	 * - one buffer being processed on the IPA
+	 */
+	static constexpr unsigned int kRkISP1InternalBufferCount = 4;
 };
 
 RkISP1Frames::RkISP1Frames(PipelineHandler *pipe)
@@ -836,17 +846,12 @@  int PipelineHandlerRkISP1::allocateBuffers(Camera *camera)
 	unsigned int ipaBufferId = 1;
 	int ret;
 
-	unsigned int maxCount = std::max({
-		data->mainPathStream_.configuration().bufferCount,
-		data->selfPathStream_.configuration().bufferCount,
-	});
-
 	if (!isRaw_) {
-		ret = param_->allocateBuffers(maxCount, &paramBuffers_);
+		ret = param_->allocateBuffers(kRkISP1InternalBufferCount, &paramBuffers_);
 		if (ret < 0)
 			goto error;
 
-		ret = stat_->allocateBuffers(maxCount, &statBuffers_);
+		ret = stat_->allocateBuffers(kRkISP1InternalBufferCount, &statBuffers_);
 		if (ret < 0)
 			goto error;
 	}
diff --git a/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp b/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp
index 5079b268..a168e0ad 100644
--- a/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp
+++ b/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp
@@ -370,8 +370,7 @@  int RkISP1Path::start()
 	if (running_)
 		return -EBUSY;
 
-	/* \todo Make buffer count user configurable. */
-	ret = video_->importBuffers(RKISP1_BUFFER_COUNT);
+	ret = video_->importBuffers(kRkISP1BufferSlotCount);
 	if (ret)
 		return ret;
 
diff --git a/src/libcamera/pipeline/rkisp1/rkisp1_path.h b/src/libcamera/pipeline/rkisp1/rkisp1_path.h
index bdf3f95b..5b53783c 100644
--- a/src/libcamera/pipeline/rkisp1/rkisp1_path.h
+++ b/src/libcamera/pipeline/rkisp1/rkisp1_path.h
@@ -76,6 +76,8 @@  private:
 	std::unique_ptr<V4L2Subdevice> resizer_;
 	std::unique_ptr<V4L2VideoDevice> video_;
 	MediaLink *link_;
+
+	static constexpr unsigned int kRkISP1BufferSlotCount = 16;
 };
 
 class RkISP1MainPath : public RkISP1Path