From: Tom Evans <tom_usenet@optusnet.com.au>
To: ajneu <ajneu1@gmail.com>, linux-can@vger.kernel.org
Subject: Re: want blocking writes, but eventually get: errno 105 (No buffer space available)
Date: Mon, 27 Jun 2016 09:24:53 +1000 [thread overview]
Message-ID: <57706445.80506@optusnet.com.au> (raw)
In-Reply-To: <loom.20160622T171459-416@post.gmane.org>
On 23/06/16 01:18, ajneu wrote:
> ajneu <ajneu1 <at> gmail.com> writes:
>
>> My test-program blocks (in write) in the beginning (the 1st few
>> program-runs), but then after a number of program-restarts I eventually get:
>> errno 105 (No buffer space available)
>> which is not acceptable, since I want to block (in the write), and not get
>> any error!!
Very old news. CAN is implemented "sort of like IP-over-Ethernet, and so has
inherited the buffering from that system. So there's a NETBUF queue. When that
one overflows you get ENOBUFS. So you can change it with:
setsockopt(pSkt->skt, SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf));
Other details here:
http://socket-can.996257.n3.nabble.com/Solving-ENOBUFS-returned-by-write-td2886.html
Search for ENOBUFS in this as well:
http://rtime.felk.cvut.cz/can/socketcan-qdisc-final.pdf
> 1st program run:
> ~> block on 33'rd write (32 frames queued)
You'll have the Network queue, the "tx_queue_len" in the driver, as well as
however many physical message buffers there are in your hardware, which looks
to be "32".
Tom
prev parent reply other threads:[~2016-06-26 23:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-22 14:39 want blocking writes, but eventually get: errno 105 (No buffer space available) ajneu
2016-06-22 15:00 ` ajneu
2016-06-22 15:52 ` Oliver Hartkopp
2016-06-22 15:18 ` ajneu
2016-06-26 23:24 ` Tom Evans [this message]
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