From mboxrd@z Thu Jan 1 00:00:00 1970 From: linas@austin.ibm.com (Linas Vepstas) Subject: Re: [PATCH 1/2]: powerpc/cell spidernet bottom half Date: Wed, 16 Aug 2006 17:55:58 -0500 Message-ID: <20060816225558.GM20551@austin.ibm.com> References: <44E34825.2020105@garzik.org> <44E38157.4070805@garzik.org> <20060816.134640.115912460.davem@davemloft.net> <200608162324.47235.arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Miller , jeff@garzik.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, jklewis@us.ibm.com, Jens.Osterkamp@de.ibm.com, akpm@osdl.org Return-path: Received: from e2.ny.us.ibm.com ([32.97.182.142]:20678 "EHLO e2.ny.us.ibm.com") by vger.kernel.org with ESMTP id S932320AbWHPW4B (ORCPT ); Wed, 16 Aug 2006 18:56:01 -0400 To: Arnd Bergmann Content-Disposition: inline In-Reply-To: <200608162324.47235.arnd@arndb.de> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Wed, Aug 16, 2006 at 11:24:46PM +0200, Arnd Bergmann wrote: > > it only > seems to be hard to make it go fast using any of them. Last round of measurements seemed linear for packet sizes between 60 and 600 bytes, suggesting that the hardware can handle a maximum of 120K descriptors/second, independent of packet size. I don't know why this is. > That may > be the fault of strange locking rules My fault; a few months ago, we were in panic mode trying to get the thing functioning reliably, and I put locks around anything and everything. This last patch removes those locks, and protects only a few pointers (the incrementing of the head and the tail pointers, and the location ofthe low watermark) that actually needed protection. They need protection because the code can get called in various different ways. > Cleaning up the TX queue only from ->poll() like all the others I'll try this ... > sounds like the right approach to simplify the code. Its not a big a driver. 'wc' says its 2.3 loc, which is 1/3 or 1/5 the size of tg3.c or the e1000*c files. --linas