From: Sowmini Varadhan <sowmini.varadhan@oracle.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: netdev <netdev@vger.kernel.org>
Subject: Re: TPACKET_V3 timeout bug?
Date: Sat, 15 Apr 2017 18:45:36 -0400 [thread overview]
Message-ID: <20170415224530.GA21010@oracle.com> (raw)
In-Reply-To: <20170415194042.GA5936@lunn.ch>
On (04/15/17 21:40), Andrew Lunn wrote:
>
> In my case, lan3 is up and idle, there are no packets flying around to
> be captured. So i would expect pcap_next_ex() to exit once a second,
> with a return value of 0. But it is not, it blocks and stays blocked.
:
> Looking at the libpcap source, the 1000ms timeout is being used as
> part of the setsockopt(3, SOL_PACKET, PACKET_RX_RING, 0xbe9445c0, 28)
> call, req.tp_retire_blk_tov is set to the timeoutval.
right, aiui, the retire_blk_tov will only kick in if we have at
least one frame in a block, but the block is not filled up yet,
before the req.tp_retire_blk_tov (1s in your case) expires.
If there are 0 frames pending, we should not be waking up the app,
so everything seems to be behaving as it should?
--Sowmini
next prev parent reply other threads:[~2017-04-15 22:45 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-15 19:40 TPACKET_V3 timeout bug? Andrew Lunn
2017-04-15 22:45 ` Sowmini Varadhan [this message]
2017-04-15 23:44 ` Andrew Lunn
2017-04-16 2:38 ` Guy Harris
2017-04-16 2:10 ` Andrew Lunn
2017-04-16 2:41 ` Guy Harris
2017-05-02 15:04 ` chetan loke
2017-05-02 17:16 ` chetan loke
2017-05-03 3:15 ` Guy Harris
2017-05-02 17:54 ` Guy Harris
2017-05-02 18:19 ` Guy Harris
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