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multiplexing issues on libcurl HTTP2

From: Bankde <>
Date: Fri, 8 Jan 2016 18:01:08 +0700

I have 2 issues while using libcurl-HTTP2 multiplexing here

I was using both curl and nghttp in dev version (I downloaded both of them on 7 Jan). Running on ubuntu 15.10.

=== First Issue: The stream max is always at 13. MAX_CONCURRENT_STREAMS reached, skip (13). ===

I was using libcurl HTTP2 sample from
I added max_connection option to make the test easier and turn off dump (since DEBUGF mode gives me better info).
I found out that the connection never updates its own MAX_CONCURRENT_STREAMS property thus being at default (13).

This is the result of running max_connection = 2 with 15 transfer. I’ve tried with 500 transfer and there is no difference.

This is the result of running nghttp2
nghttp2 is running correctly and adjust the MAX_CONCURRENT_STREAMS to 50.

I think libcurl is missing the setting frame after initialize the connection. I cannot find what’s wrong because nghttp2_submit_settings() does exist and being run during initialization (however no send/recv info are printed out). You might have some idea.

=== Second Issue: The following update (commit) causes libcurl not using multiplexed at all.

I re-downloaded new version today (8 Jan) and the problem comes from here.

I have tried both version with/without that condition and previous version seems to work fine.
I executed the same program as first issue. Here is the result:

I would like to make sure these weren't just my silly mistake (like missing some curl_option) before raising it as issue.
Thank you.

-- Bank
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Received on 2016-01-08