Attachment 110939 Details for Bug 87344 – agent: Handle EWOULDBLOCK when transmitting pseudo-TCP segments (updated)

[patch] agent: Handle EWOULDBLOCK when transmitting pseudo-TCP segments (updated)

0001-agent-Handle-EWOULDBLOCK-when-transmitting-pseudo-TC.patch (text/plain), 2.07 KB, created by Philip Withnall on 2014-12-17 08:32:31 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Philip Withnall

Created: 2014-12-17 08:32:31 UTC

Size: 2.07 KB

patch

obsolete

>From 8ecd6b89a815856b52d5931dd3a6d90fa9e85757 Mon Sep 17 00:00:00 2001
>From: Philip Withnall <philip@tecnocode.co.uk>
>Date: Mon, 15 Dec 2014 23:35:13 +0000
>Subject: [PATCH] agent: Handle EWOULDBLOCK when transmitting pseudo-TCP
> segments
>MIME-Version: 1.0
>Content-Type: text/plain; charset=UTF-8
>Content-Transfer-Encoding: 8bit
>
>The pseudo-TCP code previously didnât handle EAGAIN or EWOULDBLOCK
>errors from the low-level NiceSocket code. This caused pseudo-TCP
>connections to be dropped if the transmitting socket ever filled up,
>which could cause problems on high bandwidth connections.
>
>Fix the issue by effectively dropping the packet on EWOULDBLOCK. This
>will eventually get picked up by the pseudo-TCP recovery mechanism,
>retransmitting the packet and throttling the sender. This should
>hopefully reduce the system resource usage which caused EWOULDBLOCK in
>the first place.
>
>Spotted and debugged by RadosÅaw KoÅodziejczyk
><radek.kolodziejczyk@gmail.com>.
>
>https://bugs.freedesktop.org/show_bug.cgi?id=87344
>---
> agent/agent.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
>diff --git a/agent/agent.c b/agent/agent.c
>index a2fd46d..c0efd76 100644
>--- a/agent/agent.c
>+++ b/agent/agent.c
>@@ -1754,8 +1754,15 @@ pseudo_tcp_socket_write_packet (PseudoTcpSocket *psocket,
>           nice_address_get_port (addr));
>     }
> 
>-    if (nice_socket_send (sock, addr, len, buffer))
>+    /* Send the segment. nice_socket_send() returns 0 on EWOULDBLOCK; in that
>+     * case the segment is not sent on the wire, but we return WR_SUCCESS
>+     * anyway. This effectively drops the segment. The pseudo-TCP state machine
>+     * will eventually pick up this loss and go into recovery mode, reducing
>+     * its transmission rate and, hopefully, the usage of system resources
>+     * which caused the EWOULDBLOCK in the first place. */
>+    if (nice_socket_send (sock, addr, len, buffer) >= 0) {
>       return WR_SUCCESS;
>+    }
>   } else {
>     nice_debug ("%s: WARNING: Failed to send pseudo-TCP packet from agent %p "
>         "as no pair has been selected yet.", G_STRFUNC, component->agent);
>-- 
>1.9.3
>

Actions: View | Splinter Review

Attachments on bug 87344: 110884 | 110939

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.