VirtioGpuPipeStream: improve performance
bug: 146066070
We don't need to wait after every transfer ioctl; allow
more than one in flight, and wait them out less often.
Change-Id: I8c7db54e8610ea87e1c14ac39812196d208464c9
diff --git a/system/OpenglSystemCommon/VirtioGpuPipeStream.cpp b/system/OpenglSystemCommon/VirtioGpuPipeStream.cpp
index 6a75354..3718571 100644
--- a/system/OpenglSystemCommon/VirtioGpuPipeStream.cpp
+++ b/system/OpenglSystemCommon/VirtioGpuPipeStream.cpp
@@ -48,7 +48,8 @@
m_bufsize(bufSize),
m_buf(nullptr),
m_read(0),
- m_readLeft(0) { }
+ m_readLeft(0),
+ m_writtenPos(0) { }
VirtioGpuPipeStream::~VirtioGpuPipeStream()
{
@@ -329,6 +330,7 @@
if (ret) {
ERR("VirtioGpuPipeStream: DRM_IOCTL_VIRTGPU_WAIT failed with %d (%s)\n", errno, strerror(errno));
}
+ m_writtenPos = 0;
}
ssize_t VirtioGpuPipeStream::transferToHost(const void* buffer, size_t len) {
@@ -338,16 +340,21 @@
struct drm_virtgpu_3d_transfer_to_host xfer;
unsigned char* virtioPtr = m_virtio_mapped;
+
const unsigned char* readPtr = reinterpret_cast<const unsigned char*>(buffer);
while (done < len) {
size_t toXfer = todo > kTransferBufferSize ? kTransferBufferSize : todo;
- memcpy(virtioPtr, readPtr, toXfer);
+ if (toXfer > (kTransferBufferSize - m_writtenPos)) {
+ wait();
+ }
+
+ memcpy(virtioPtr + m_writtenPos, readPtr, toXfer);
memset(&xfer, 0, sizeof(xfer));
xfer.bo_handle = m_virtio_bo;
- xfer.box.x = 0;
+ xfer.box.x = m_writtenPos;
xfer.box.y = 0;
xfer.box.w = toXfer;
xfer.box.h = 1;
@@ -360,11 +367,18 @@
return (ssize_t)ret;
}
- wait();
-
done += toXfer;
readPtr += toXfer;
todo -= toXfer;
+
+ // Note; One does not simply increment |m_writtenPos| by exactly
+ // |toXfer| because the way the underlying memory works (esp going
+ // through TTM/GEM), we have no guarantee that things will stay
+ // coherent byte-by-byte as it gets to the host. To be safe, skip a
+ // page each time.
+ const size_t kWrittenPosIncrement = PAGE_SIZE;
+ m_writtenPos += ((toXfer + kWrittenPosIncrement - 1) /
+ kWrittenPosIncrement) * kWrittenPosIncrement;
}
return len;
@@ -379,6 +393,10 @@
const unsigned char* virtioPtr = m_virtio_mapped;
unsigned char* readPtr = reinterpret_cast<unsigned char*>(buffer);
+ if (m_writtenPos) {
+ wait();
+ }
+
while (done < len) {
size_t toXfer = todo > kTransferBufferSize ? kTransferBufferSize : todo;
diff --git a/system/OpenglSystemCommon/VirtioGpuPipeStream.h b/system/OpenglSystemCommon/VirtioGpuPipeStream.h
index bc17b2b..31366f3 100644
--- a/system/OpenglSystemCommon/VirtioGpuPipeStream.h
+++ b/system/OpenglSystemCommon/VirtioGpuPipeStream.h
@@ -49,7 +49,7 @@
int getSocket() const;
private:
- // sync
+ // sync. Also resets the write position.
void wait();
// transfer to/from host ops
@@ -68,5 +68,7 @@
size_t m_read;
size_t m_readLeft;
+ size_t m_writtenPos;
+
VirtioGpuPipeStream(int sock, size_t bufSize);
};
