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. - Leo _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev