Slow download speed
clowwindy opened this issue · comments
According to SPDY Protocol - Draft 3.1
The receiver of a frame sends a WINDOW_UPDATE frame as it consumes data and frees up space in flow control windows. Separate WINDOW_UPDATE frames are sent for the stream and connection level flow control windows.
But node-spdy only sends WINDOW_UPDATE frames when window size is 0. Therefore when download speed is around 500KB/s the speed is limited by RTT.
// connection.js
// ### function sendWindowUpdate (force)
// #### @force {Boolean} send even if windowSize is positive
// Send WINDOW_UPDATE if needed
//
Connection.prototype._sendWindowUpdate = function sendWindowUpdate(force) {
var state = this._spdyState;
if (state.version < 3.1 && (!state.isServer || !state.autoSpdy31) ||
state.windowSize > 0 && !force) {
return;
}
// ...
}