经典好文推荐，通过阅读本文，您将收获以下知识点:

一、Systrace 拆解概览
二、Systrace 阶段拆解详解

一、Systrace 拆解概览

MTK Camera 照片切换视频trace 拆解(非切换摄像头类)

照片切换视频	模块	trace 关键字
S0	Camera APP	deliverInputEvent ⇒ abortCaptures/CameraHal::flush 开始
S1	Camera HAL	abortCaptures/CameraHal::flush
S2	Camera APP	abortCaptures/CameraHal::flush 结束 ⇒ CameraHal::configureStreams start
S3	Camera HAL	CameraHal::configureStreams
S4	Camera APP	CameraHal::configureStreams end ⇒ setRepeatingRequest start
S5	Camera HAL	setRepeatingRequest start ⇒ first full buffer
S6	Camera APP、SF	first full buffer ⇒ 第一帧显示(onPreviewOk)

二、Systrace 阶段拆解详解

2.1 点击照片模式切换视频模式

S0 deliverInputEvent ⇒ abortCapture/CameraHal::flush 开始

Camera 响应点击事件开始abortCapture

Systrace 关键字：
Camera app 点击照片切换视频模式响应：deliverInputEvent
Camera app 下发停止预览请求：abortCaptures
Camera FWK 响应abortcapture 的处理： flush 、CameraHal::flush

S1 abortCaptures/CameraHal::flush

CameraHAL 响应flush的流程

StreamingNode flush

Systrace 关键字：
StreamingNode::flush
P2_Dispatch:notifyFlush()
P2_Streaming:notifyFlush()

P2_Dispatch:waitFlush()
P2_Streaming:waitFlush()

CaptureNode flush

Systrace 关键字：
CaptureNode::flush
P2_Capture:notifyFlush()
P2_Capture:waitFlush()

S2 abortCaptures/CameraHal::flush 结束 ⇒ CameraHal::configureStreams start

初始化videomode,MediaRecorder ，prepare MediaRecorder

Systrace 关键字：
videoMode.doInitMode
AIDL::cpp::ICameraService::getNumberOfCameras::cppClient

videoMode.mediaRecorderinit
videoMode.mediaRecorderPrepare

Camera APP通过bind 跟mediaserver 进行通讯，并创建createRecord

createRecord 实例

AIDL::cpp::IAudioFlingerService::createRecord::cppClient

S3 CameraHal::configureStreams

configureStreams 概览

Systrace 关键字：
createCaptureSession
endConfigure
configureStreams
configureStreamsLocked
CameraHal::configureStreams

Delete3路照片流

Systrace 关键字：
deleteStream
disconnect
freeBuffer

创建3路视频流

Systrace 关键字：
AIDL::cpp::ICameraDeviceUser::createStream::cppServer
createStream

Camera HAL CaptureNode ，StreamNode uninit

Systrace 关键字：
StreamingNode::flush
CaptureNode::flush
CaptureNode::uninit
StreamingNode::uninit

StreamingNode flush && CaptureNode flush

StreamingNode flush

Systrace 关键字：
StreamingNode::flush
P2_Dispatch:waitFlush()
P2_Streaming:waitFlush()
P2_Dispatch:notifyFlush()
P2_Streaming:notifyFlush()

CaptureNode flush

Systrace 关键字：
CaptureNode::flush
P2_Capture:waitFlush()
P2_Capture:notifyFlush()

CaptureNode uninit &&StreamingNode uninit

CaptureNode uninit

CaptureNode::uninit
P2_Capture:uninit()

StreamingNode uninit

StreamingNode::uninit
P2_Dispatch:uninit()
P2_Streaming:uninit()
releaseGeneralPipe
uninit
uninitPool
fpipe.p2g.fullImg.destroy
~GraphicBuffer
free
freeBuffer
TPI uninit
uninitHalISP
StreamingNode::uninitLock
uninit3DNR
uninitDsdnPools
releaseBuffer
fpipe.fullImg.destroy
uninitNodes
uninitSMVR

Camera HAL 决策配流Feature evaluateConfiguration

Systrace 关键字：
configureStreams
eatureSettingPolicy::evaluateConfiguration
evaluateCaptureConfiguration
updateStreamConfiguration

为申请的3路视频流申请buffers

Systrace 关键字：
configureStreams
initProducer-Hal:Image:FD
initProducer-Hal:Image:P1:Resizeraw_main1
initProducer-Hal:Image:STT_main1
allocateBuffers
endConfigure dump

Camera FWK 配流结束 finishConfiguration

Systrace 关键字：
endConfigure
finishConfiguration

Camera FWK 配流结束 finishConfiguration 的同时 FdNode init

,StreamNode init,CaptureNode init

Systrace 关键字：
finishConfiguration
FdNode init
StreamingNode::init
CaptureNode::init
submitRequestList

StreamingNode::init

Systrace 关键字：
StreamingNode::init
P2_Dispatch:init()
P2_Streaming:FeaturePipe create
prepareGeneralPipe
P2_Streaming:FeaturePipe init
TPI init_config

CaptureNode::init && config

Systrace 关键字：
CaptureNode::init
P2_Capture:init()
P2_Capture:FeaturePipe create & init
CaptureNode::config
P2_Capture:config()

S4：CameraHal::configureStreams 结束 -->submitRequestList

CameraHal::configureStreams 结束 -->submitRequestList 下发预览请求 trace TAG

submitRequestList 下发预览请求

Sysrace TAG:
AIDL::cpp::ICameraDeviceUser::submitRequestList::cppServer
submitRequestList
setStreamingRequestList
submitRequestsHelper
setRepeatingRequests

S5：submitRequestList --> first full buffer

第一帧预览请求

第一帧预览请求 Trace

Camera FWK trace TAG：
sendRequestsBatch
CameraHal::processBatchCaptureRequests
frame capture

Camera HAL trace TAG：
processCaptureRequest

第一帧出图callback 请求

第一帧出图定位： callback Camera FWK 关键trace TAG

Trace TAG:
processCaptureResults
Stream 0: first full buffer

第一帧出图callback Camera HAL --> Camera FWK -->Camera APP

第一帧callback 流程（Camera HAL -->Camera FWK）

第一帧出图callback Camera HAL trace TAG
processCaptureResult
第一帧出图callback Camera FWK 关键 trace TAG：first full buffer
Stream 0: first full buffer
frame capture

第一帧callback 流程（Camera FWK -->Camera APP）

Camera APP trace TAG:
SurfaceTexture

S6： first full buffer ⇒ 第一帧显示(onPreviewOk)

第一帧callback 流程（Camera APP -->SurfaceFliger 送显示）

SF 显示trace TAG：
surfaceflinger
vsync-sf
BufferTx
Fence