[jira] [Created] (TS-3185) Increase the default spdy initial_window_size_in setting to 1 mb

["Sudheer Vinukonda (JIRA)" <ji...@apache.org>]

Sudheer Vinukonda created TS-3185:
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             Summary: Increase the default spdy initial_window_size_in setting to 1 mb
                 Key: TS-3185
                 URL: https://issues.apache.org/jira/browse/TS-3185
             Project: Traffic Server
          Issue Type: Improvement
          Components: SPDY
            Reporter: Sudheer Vinukonda


Currently, proxy.config.spdy.initial_window_size_in is set to the default value 64K (suggested in
http://www.chromium.org/spdy/spdy-protocol/spdy-protocol-draft3-1). This suggested value is perhaps due to historic reasons when the window_size was only allowed 2 octets in the older spdy versions.

Note that, ideally, the client (sender) should still be able to defer the upload when the send window is exhausted until the server (receiver) sends an WINDOW_UPDATE frame indicating to resume the sending. 

Even so, 64K may still be too small and may result in increasing upload
latencies, especially, in case of large concurrent upload scenarios. Hence, I would like to bump up the default value for the spdy initial window
size to a higher value (preferably, 1 mb that more popular spdy enabled web servers are using).

Here's some basic benchmarking data:

5 parallel uploads from APAC to the US with totally 2,299,250 bytes.

spdy=off, 2.34 secs
spdy=on, spdy.initial_window_size_in=64k: 11.28 secs
spdy=on, spdy.initial_window_size_in=1M:   1.99 secs
spdy=on, spdy.initial_window_size_in=10M:  2.01 secs




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