netdev - RE: TCP socket send return EAGAIN unexpectedly when sending small fragments

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Date:   Fri, 10 Jun 2022 15:21:30 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Ronny Meeus' <ronny.meeus@...il.com>,
        Eric Dumazet <erdnetdev@...il.com>
CC:     netdev <netdev@...r.kernel.org>
Subject: RE: TCP socket send return EAGAIN unexpectedly when sending small
 fragments

...
> If the 5 queued packets on the sending side would cause the EAGAIN
> issue, the real question maybe is why the receiving side is not
> sending the ACK within the 10ms while for earlier messages the ACK is
> sent much sooner.

Have you disabled Nagle (TCP_NODELAY) ?

Nagle only really works for bulk data transfer (large sends)
and interactive sessions (command - response).
For nearly everything else it adds unwanted 100ms delays.

	David

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