Date: Sat, 22 Mar 2014 22:28:53 +0400 From: Gleb Smirnoff <glebius@FreeBSD.org> To: Andrew Rybchenko <Andrew.Rybchenko@oktetlabs.ru> Cc: net@FreeBSD.org Subject: Re: [PATCH 2/6] sfxge: limit software Tx queue size Message-ID: <20140322182852.GW1499@glebius.int.ru> In-Reply-To: <532D62F8.4080103@oktetlabs.ru> References: <532817F5.8010505@oktetlabs.ru> <20140318132440.GG1499@FreeBSD.org> <532D62F8.4080103@oktetlabs.ru>
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Andrew, On Sat, Mar 22, 2014 at 02:16:24PM +0400, Andrew Rybchenko wrote: A> > The interaction between sfxge_tx_qdpl_put() and sfxge_tx_packet_add() A> > is quite complex and I couldn't resist from suggesting you to A> > simplify the code. A> > A> > Can you please look into attached patch? A> > A> > - Inline sfxge_tx_qdpl_put() into sfxge_tx_packet_add(). A> > - Simplify the 'locked' logic. A> > - Add your PATCH 1/6, the mbuf leak fix. A> > - Add your PATCH 2/6, the SFXGE_TX_DPL_GET_PKT_LIMIT_DEFAULT check. A> I don't like "locked" flag passed to qdpl_put() function as well. A> However, I prefer to keep patches granular and avoid mixing of different A> changes in single patch. If the initial patch is OK, please, submit it A> to repository. Then, I'll rebase your patch, discuss it locally and come A> back to you. As you wish. Committed, thanks. A> BTW, I see that many drivers use drbr for software Tx queue. What do you A> think, would it be beneficial to use it instead of the list implemented A> here? No idea. drbr(9) is definitely better than ifqueue(9), that's all I can confident state. No idea how drbr(4) compares to the hand made queue of sxfge(4). You've got the hardware, you measure :) Btw, there are some opinions that with modern cards any software queing is a bad idea. Driver should simply hold as much as hardware tx ring can hold. There is no yet stable decision about this, just thoughts floating around. -- Totus tuus, Glebius.
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