From a520c179b89610248ef97f614d6b831ccee54c6b Mon Sep 17 00:00:00 2001 From: Timur Pocheptsov Date: Thu, 12 Oct 2017 15:02:09 +0200 Subject: HTTP/2 protocol handler: tweak receive window sizes We were using the default ones, provided by RFC7540. It appears they are way too restrictive and conservative: when downloading something relatively big, a stream keeps spending the whole session/its own 'recv' windows and thus we have to constantly send WINDOW_UPDATE frames. This significantly slows down our HTTP/2 implementation, making it orders of magnitude slower than HTTP/1.1. To fix this: - We send SETTINGS_INITIAL_WINDOW_SIZE in the first SETTINGS frame to inform our peer that per-stream WINDOW is bigger than 64Kb - We increase the session's receive window size. Task-number: QTBUG-63722 Change-Id: I31312fcfd5f0fc0aee6aaa5d3562cc7d1b931adc Reviewed-by: Edward Welbourne --- src/network/access/http2/http2protocol.cpp | 2 ++ src/network/access/http2/http2protocol_p.h | 14 +++++++++++-- src/network/access/qhttp2protocolhandler.cpp | 31 +++++++++++++--------------- src/network/access/qhttp2protocolhandler_p.h | 8 ++----- 4 files changed, 30 insertions(+), 25 deletions(-) (limited to 'src/network') diff --git a/src/network/access/http2/http2protocol.cpp b/src/network/access/http2/http2protocol.cpp index 54811aeab0..bb3d6bf575 100644 --- a/src/network/access/http2/http2protocol.cpp +++ b/src/network/access/http2/http2protocol.cpp @@ -216,6 +216,8 @@ Frame default_SETTINGS_frame() // MAX frame size (16 kb), disable/enable PUSH_PROMISE builder.append(Settings::MAX_FRAME_SIZE_ID); builder.append(quint32(maxFrameSize)); + builder.append(Settings::INITIAL_WINDOW_SIZE_ID); + builder.append(initialStreamReceiveWindowSize); builder.append(Settings::ENABLE_PUSH_ID); builder.append(quint32(is_PUSH_PROMISE_enabled())); diff --git a/src/network/access/http2/http2protocol_p.h b/src/network/access/http2/http2protocol_p.h index b26ff0e9f4..c64e960002 100644 --- a/src/network/access/http2/http2protocol_p.h +++ b/src/network/access/http2/http2protocol_p.h @@ -129,10 +129,20 @@ enum Http2PredefinedParameters maxConcurrentStreams = 100 // HTTP/2, 6.5.2 }; -// It's int, it has internal linkage, it's ok to have it in headers - -// no ODR violation is possible. +// These are ints, const, they have internal linkage, it's ok to have them in +// headers - no ODR violation. const quint32 lastValidStreamID((quint32(1) << 31) - 1); // HTTP/2, 5.1.1 +// The default size of 64K is too small and limiting: if we use it, we end up +// sending WINDOW_UPDATE frames on a stream/session all the time, for each +// 2 DATE frames of size 16K (also default) we'll send a WINDOW_UPDATE frame +// for a given stream and have a download speed order of magnitude lower than +// our own HTTP/1.1 protocol handler. We choose a bigger window size (normally, +// HTTP/2 servers are not afraid to immediately set it to possible max anyway) +// and split this window size between our concurrent streams. +const qint32 initialSessionReceiveWindowSize = defaultSessionWindowSize * 10000; +const qint32 initialStreamReceiveWindowSize = initialSessionReceiveWindowSize / maxConcurrentStreams; + extern const Q_AUTOTEST_EXPORT char Http2clientPreface[clientPrefaceLength]; void prepare_for_protocol_upgrade(QHttpNetworkRequest &request); diff --git a/src/network/access/qhttp2protocolhandler.cpp b/src/network/access/qhttp2protocolhandler.cpp index a651fc4092..461f2429b3 100644 --- a/src/network/access/qhttp2protocolhandler.cpp +++ b/src/network/access/qhttp2protocolhandler.cpp @@ -161,8 +161,6 @@ bool sum_will_overflow(qint32 windowSize, qint32 delta) using namespace Http2; const std::deque::size_type QHttp2ProtocolHandler::maxRecycledStreams = 10000; -const qint32 QHttp2ProtocolHandler::sessionMaxRecvWindowSize; -const qint32 QHttp2ProtocolHandler::streamInitialRecvWindowSize; const quint32 QHttp2ProtocolHandler::maxAcceptableTableSize; QHttp2ProtocolHandler::QHttp2ProtocolHandler(QHttpNetworkConnectionChannel *channel) @@ -374,12 +372,10 @@ bool QHttp2ProtocolHandler::sendClientPreface() if (!frameWriter.write(*m_socket)) return false; - sessionRecvWindowSize = sessionMaxRecvWindowSize; - if (defaultSessionWindowSize < sessionMaxRecvWindowSize) { - const auto delta = sessionMaxRecvWindowSize - defaultSessionWindowSize; - if (!sendWINDOW_UPDATE(connectionStreamID, delta)) - return false; - } + sessionRecvWindowSize = Http2::initialSessionReceiveWindowSize; + const auto delta = Http2::initialSessionReceiveWindowSize - Http2::defaultSessionWindowSize; + if (!sendWINDOW_UPDATE(Http2::connectionStreamID, delta)) + return false; prefaceSent = true; waitingForSettingsACK = true; @@ -549,20 +545,20 @@ void QHttp2ProtocolHandler::handleDATA() if (inboundFrame.flags().testFlag(FrameFlag::END_STREAM)) { finishStream(stream); deleteActiveStream(stream.streamID); - } else if (stream.recvWindow < streamInitialRecvWindowSize / 2) { + } else if (stream.recvWindow < Http2::initialStreamReceiveWindowSize / 2) { QMetaObject::invokeMethod(this, "sendWINDOW_UPDATE", Qt::QueuedConnection, Q_ARG(quint32, stream.streamID), - Q_ARG(quint32, streamInitialRecvWindowSize - stream.recvWindow)); - stream.recvWindow = streamInitialRecvWindowSize; + Q_ARG(quint32, Http2::initialStreamReceiveWindowSize - stream.recvWindow)); + stream.recvWindow = Http2::initialStreamReceiveWindowSize; } } } - if (sessionRecvWindowSize < sessionMaxRecvWindowSize / 2) { + if (sessionRecvWindowSize < Http2::initialSessionReceiveWindowSize / 2) { QMetaObject::invokeMethod(this, "sendWINDOW_UPDATE", Qt::QueuedConnection, Q_ARG(quint32, connectionStreamID), - Q_ARG(quint32, sessionMaxRecvWindowSize - sessionRecvWindowSize)); - sessionRecvWindowSize = sessionMaxRecvWindowSize; + Q_ARG(quint32, Http2::initialSessionReceiveWindowSize - sessionRecvWindowSize)); + sessionRecvWindowSize = Http2::initialSessionReceiveWindowSize; } } @@ -1203,7 +1199,7 @@ quint32 QHttp2ProtocolHandler::createNewStream(const HttpMessagePair &message, b const Stream newStream(message, newStreamID, streamInitialSendWindowSize, - streamInitialRecvWindowSize); + Http2::initialStreamReceiveWindowSize); if (!uploadDone) { if (auto src = newStream.data()) { @@ -1398,7 +1394,8 @@ bool QHttp2ProtocolHandler::tryReserveStream(const Http2::Frame &pushPromiseFram promise.reservedID = reservedID; promise.pushHeader = requestHeader; - activeStreams.insert(reservedID, Stream(urlKey, reservedID, streamInitialRecvWindowSize)); + activeStreams.insert(reservedID, Stream(urlKey, reservedID, + Http2::initialStreamReceiveWindowSize)); return true; } @@ -1432,7 +1429,7 @@ void QHttp2ProtocolHandler::initReplyFromPushPromise(const HttpMessagePair &mess // Let's pretent we're sending a request now: Stream closedStream(message, promise.reservedID, streamInitialSendWindowSize, - streamInitialRecvWindowSize); + Http2::initialStreamReceiveWindowSize); closedStream.state = Stream::halfClosedLocal; activeStreams.insert(promise.reservedID, closedStream); promisedStream = &activeStreams[promise.reservedID]; diff --git a/src/network/access/qhttp2protocolhandler_p.h b/src/network/access/qhttp2protocolhandler_p.h index 82eea21818..b52f8ae10c 100644 --- a/src/network/access/qhttp2protocolhandler_p.h +++ b/src/network/access/qhttp2protocolhandler_p.h @@ -176,13 +176,9 @@ private: quint32 maxConcurrentStreams = Http2::maxConcurrentStreams; // Control flow: - static const qint32 sessionMaxRecvWindowSize = Http2::defaultSessionWindowSize * 10; - // Signed integer, it can become negative (it's still a valid window size): - qint32 sessionRecvWindowSize = sessionMaxRecvWindowSize; - // We do not negotiate this window size - // We have to send WINDOW_UPDATE frames to our peer also. - static const qint32 streamInitialRecvWindowSize = Http2::defaultSessionWindowSize; + // Signed integer, it can become negative (it's still a valid window size): + qint32 sessionRecvWindowSize = Http2::initialSessionReceiveWindowSize; // Updated by SETTINGS and WINDOW_UPDATE. qint32 sessionSendWindowSize = Http2::defaultSessionWindowSize; -- cgit v1.2.3