From: Laszlo Ersek <lersek@redhat.com>
To: Wei Liu <wei.liu2@citrix.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"jeremy@goop.org" <jeremy@goop.org>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
Ian Campbell <Ian.Campbell@citrix.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [Xen-devel] [PATCH] xen-netfront: correct MAX_TX_TARGET calculation.
Date: Fri, 03 Feb 2012 13:59:56 +0100 [thread overview]
Message-ID: <4F2BDA4C.7060601@redhat.com> (raw)
In-Reply-To: <4F2BD2CC.4050906@redhat.com>
On 02/03/12 13:27, Laszlo Ersek wrote:
> On 01/27/12 11:36, Wei Liu wrote:
>> As the tx structure is bigger than rx structure. I think scratch space
>> size is likely to shrink after correction.
>
> It also seems to affect the netfront_tx_slot_available() function,
> making it stricter (likely). Before the patch, the function may have
> reported available slots when there were none, causing spurious(?) queue
> wakeups in xennet_maybe_wake_tx(), and not stopping the queue in
> xennet_start_xmit() when it should have(?).
(Eyeballing the source makes me think
NET_TX_RING_SIZE == (4096 - 16 - 48) / (5 * 4) == 201
NET_RX_RING_SIZE == (4096 - 16 - 48) / (4 * 4) == 252
but I didn't try to verify them.)
Laszlo
next prev parent reply other threads:[~2012-02-03 12:58 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-26 17:23 [PATCH] xen-netfront: correct MAX_TX_TARGET calculation Wei Liu
2012-01-26 18:19 ` Konrad Rzeszutek Wilk
2012-01-27 10:36 ` Wei Liu
2012-02-03 12:27 ` [Xen-devel] " Laszlo Ersek
2012-02-03 12:59 ` Laszlo Ersek [this message]
2012-02-03 13:26 ` Jan Beulich
2012-02-03 13:39 ` Laszlo Ersek
2012-01-26 18:48 ` David Miller
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