From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vineet Gupta Subject: Re: [PATCH] ethernet/arc/arc_emac: Fix huge delays in large file copies Date: Tue, 10 Sep 2013 11:57:30 +0530 Message-ID: <522EBBD2.1060003@synopsys.com> References: <1378295235-18928-1-git-send-email-vgupta@synopsys.com> <20130905.142530.732425484460470485.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Cc: David Miller , , , , , "stable@vger.kernel.org" To: greg Kroah-Hartman Return-path: In-Reply-To: <20130905.142530.732425484460470485.davem@davemloft.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 09/05/2013 11:55 PM, David Miller wrote: > From: Vineet Gupta > Date: Wed, 4 Sep 2013 17:17:15 +0530 > >> copying large files to a NFS mounted host was taking absurdly large >> time. >> >> Turns out that TX BD reclaim had a sublte bug. >> >> Loop starts off from @txbd_dirty cursor and stops when it hits a BD >> still in use by controller. However when it stops it needs to keep the >> cursor at that very BD to resume scanning in next iteration. However it >> was erroneously incrementing the cursor, causing the next scan(s) to >> fail too, unless the BD chain was completely drained out. >> >> [ARCLinux]$ ls -l -sh /disk/log.txt >> 17976 -rw-r--r-- 1 root root 17.5M Sep /disk/log.txt >> >> ========== Before ===================== >> [ARCLinux]$ time cp /disk/log.txt /mnt/. >> real 31m 7.95s >> user 0m 0.00s >> sys 0m 0.10s >> >> ========== After ===================== >> [ARCLinux]$ time cp /disk/log.txt /mnt/. >> real 0m 24.33s >> user 0m 0.00s >> sys 0m 0.19s >> >> Signed-off-by: Vineet Gupta > > Applied. > Hi Greg, This needs a stable backport (3.11). Mainline commit 27082ee1b92f4d41e78b85 Thx, -Vineet