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From Stefan Eissing <>
Subject Re: No H2 Window updates!
Date Fri, 04 Dec 2015 15:23:19 GMT
If you find the time, the lastest v1.0.10 mod_http2 in 2.4.x sets the connection window to
max which addresses for me the window starvation issues I was able to reproduce (and put into
my test suite). I hope this works for you as well, otherwise I'd need more detailed data on
how to reproduce the hanger.


> Am 04.12.2015 um 10:50 schrieb Bert Huijben <>:
>> -----Original Message-----
>> From: Stefan Eissing []
>> Sent: vrijdag 4 december 2015 10:18
>> To:
>> Subject: Re: No H2 Window updates!
>> That is unfortunate. I added a test case which reproduced window
>> exhaustion before I fixed it. What sort of requests do still miss window
>> updates? content-length? response codes?
> I don't think we send content-length headers... (see older problem). I fixed
> Subversion to always send Content-Type though.
> I'm going to add some more tracing to get the details again, but from what I
> remember is that I had requests with 113 and 128 bytes +- over and over.
> [The tool experiencing this problem is a tool that tries to replicate some
> behavior we can't express in Subversion yet. To implement this it asks the
> server for similar things over and over. If we decide that we go this way we
> would probably send one advanced request and get one response from the
> server... But currently it is a nice tool to test the network IO limits :-)]
> These requests are always 1 HEADERS (/endofheaders) + 1 DATA (/eos) and the
> response is not much either (Certainly less than 1 Kbyte, so probably just
> HEADERS+1 DATA as well)
> ----------------------
> Ok, added some logging back.
> I still don't see a lot of window updates, but I do see some.
> After my connection windows is slightly below 32767... I receive a single
> connection window update to bring it back to exactly 32767. In all cases in
> this log this update is < 100 bytes. (1 <= update < 256).
> But then I don't receive further window updates until my connection window
> is almost depleted... And then I get another 255 bytes or so. Not enough to
> get through the test.
> The log I just used is on:
> (Search for 'DBG: Connection window update' to find the updates between the
> allocations)
> 	Bert

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