From 5ab1fc7674480fba1f51652d9cc67d0b7ffa5ff0 Mon Sep 17 00:00:00 2001
From: Dean Lee <deanlee3@gmail.com>
Date: Wed, 13 Dec 2023 11:15:47 +0800
Subject: [PATCH] encoder: reduce memory allocations and copying (#28704)

* reduce memory allocations and copying

* #include <vector>
old-commit-hash: a4179a7c230e687bebd15581ccdb3f7d34a690f4
---
 system/loggerd/encoder/encoder.cc | 11 +++++++----
 system/loggerd/encoder/encoder.h  |  3 ++-
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/system/loggerd/encoder/encoder.cc b/system/loggerd/encoder/encoder.cc
index 869b4617b3..0aba4b8b49 100644
--- a/system/loggerd/encoder/encoder.cc
+++ b/system/loggerd/encoder/encoder.cc
@@ -27,8 +27,11 @@ void VideoEncoder::publisher_publish(VideoEncoder *e, int segment_num, uint32_t
   edat.setData(dat);
   if (flags & V4L2_BUF_FLAG_KEYFRAME) edat.setHeader(header);
 
-  auto words = new kj::Array<capnp::word>(capnp::messageToFlatArray(msg));
-  auto bytes = words->asBytes();
-  e->pm->send(e->encoder_info.publish_name, bytes.begin(), bytes.size());
-  delete words;
+  uint32_t bytes_size = capnp::computeSerializedSizeInWords(msg) * sizeof(capnp::word);
+  if (e->msg_cache.size() < bytes_size) {
+    e->msg_cache.resize(bytes_size);
+  }
+  kj::ArrayOutputStream output_stream(kj::ArrayPtr<capnp::byte>(e->msg_cache.data(), bytes_size));
+  capnp::writeMessage(output_stream, msg);
+  e->pm->send(e->encoder_info.publish_name, e->msg_cache.data(), bytes_size);
 }
diff --git a/system/loggerd/encoder/encoder.h b/system/loggerd/encoder/encoder.h
index a8bfd5c054..9c23928cc6 100644
--- a/system/loggerd/encoder/encoder.h
+++ b/system/loggerd/encoder/encoder.h
@@ -4,6 +4,7 @@
 #include <cstdint>
 #include <memory>
 #include <thread>
+#include <vector>
 
 #include "cereal/messaging/messaging.h"
 #include "cereal/visionipc/visionipc.h"
@@ -23,7 +24,6 @@ public:
 
   static void publisher_publish(VideoEncoder *e, int segment_num, uint32_t idx, VisionIpcBufExtra &extra, unsigned int flags, kj::ArrayPtr<capnp::byte> header, kj::ArrayPtr<capnp::byte> dat);
 
-
 protected:
   int in_width, in_height;
   const EncoderInfo encoder_info;
@@ -32,4 +32,5 @@ private:
   // total frames encoded
   int cnt = 0;
   std::unique_ptr<PubMaster> pm;
+  std::vector<capnp::byte> msg_cache;
 };