On Mon, Mar 30, 2009 at 6:01 PM, Joakim Tjernlund <joakim.tjernl...@transmode.se> wrote: > pku....@gmail.com wrote on 30/03/2009 11:36:36: >> >> On Mon, Mar 30, 2009 at 5:21 PM, Joakim Tjernlund >> <joakim.tjernl...@transmode.se> wrote: >> > pku....@gmail.com wrote on 30/03/2009 10:34:47: >> >> >> >> On Thu, Mar 26, 2009 at 1:51 AM, Joakim Tjernlund >> >> <joakim.tjernl...@transmode.se> wrote: >> >> > Anton Vorontsov <avoront...@ru.mvista.com> wrote on 25/03/2009 >> > 15:25:40: >> >> >> On Wed, Mar 25, 2009 at 02:30:49PM +0100, Joakim Tjernlund wrote: >> >> >> > >>From 1c2f23b1f37f4818c0fd0217b93eb38ab6564840 Mon Sep 17 > 00:00:00 >> >> > 2001 >> >> >> > From: Joakim Tjernlund <joakim.tjernl...@transmode.se> >> >> >> > Date: Tue, 24 Mar 2009 10:19:27 +0100 >> >> >> > Subject: [PATCH] ucc_geth: Move freeing of TX packets to NAPI >> > context. >> >> >> > Also increase NAPI weight somewhat. >> >> >> > This will make the system alot more responsive while >> >> >> > ping flooding the ucc_geth ethernet interaface. >> >> >> >> >> >> Some time ago I've tried a similar thing for this driver, but > during >> >> >> tcp (or udp I don't quite remember) netperf tests I was getting tx >> >> >> watchdog timeouts after ~2-5 minutes of work. I was testing with a >> >> >> gigabit and 100 Mbit link, with 100 Mbit link the issue was not >> >> >> reproducible. >> >> >> >> >> >> Though, I recalling I was doing a bit more than your patch: I was >> >> >> also clearing the TX events in the ucce register before calling >> >> >> ucc_geth_tx, that way I was trying to avoid stale interrupts. That >> >> >> helped to increase an overall performance (not only > responsiveness), >> >> >> but as I said my approach didn't pass the tests. >> >> >> >> >> >> I don't really think that your patch may cause this, but can you >> >> >> try netperf w/ this patch applied anyway? And see if it really >> >> >> doesn't cause any issues under stress? >> >> > >> >> > Does the line(in ucc_geth_tx()) look OK to you: >> >> > if ((bd == ugeth->txBd[txQ]) && (netif_queue_stopped(dev) == >> > 0)) >> >> > break; >> >> > >> >> > Sure does look fishy to me. >> >> >> >> There are two cases when txBd=ConfBd: the BD ring is full or empty. >> >> The condition used here ensures that it is the empty case. Because > in >> >> hard_start_xmit, the queue will be stopped when the BD ring is full. >> >> Maybe some comment is needed here. >> > >> > But how do you know that the queue hasn't been stopped by someone else >> > than >> > the driver? >> > If it is stopped by higher layers, the if stmt will fail. >> >> It looks like from existing code that only the driver can legally stop >> the queue. I'm not 100% sure though. Correct me if I'm wrong. > > I don't know. But the question you should ask is: Does the networking > code promise this now and for the future?
Right. But it's beyond my knowledge to answer this question. If not, adding a device specific flag is not very costing. Hi Dave, Can we assume that the netif_stop_queue() and netif_wake_queue() are only used by the netdev driver? And the queue state will not be changed by other part of the networking subsystem? - Leo _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
