From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from pentafluge.infradead.org ([213.146.154.40]:47966 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750823AbXHaXzm (ORCPT ); Fri, 31 Aug 2007 19:55:42 -0400 Subject: Re: b43legacy woes From: David Woodhouse To: Larry Finger Cc: david@identd.dyndns.org, wireless , bcm43xx-dev In-Reply-To: <46D8957D.2010705@lwfinger.net> References: <46D8957D.2010705@lwfinger.net> Content-Type: text/plain; charset=UTF-8 Date: Sat, 01 Sep 2007 00:55:35 +0100 Message-Id: <1188604535.985.277.camel@pmac.infradead.org> Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Fri, 2007-08-31 at 17:26 -0500, Larry Finger wrote: > The poor performance of the BCM4306/2 (your chip/card) is known. Ther= e has been a report that this=20 > is a regression since 2.6.20, or so, has not been confirmed. With a 2= =2E6.21 kernel, I got an iperf=20 > transmit rate of 4 Mbs, but that quickly dropped to 0.3 Mbs without m= e changing anything - I just=20 > repeated the iperf command.=20 That reminds me... I accidentally invented a new wireless test. It's intended to stream the full OS images to OLPC laptops on the production line, and does so by multicast -- so there are no link-layer ACKs and retries compensating for your packet loss; it all gets reported. It's in git://git.infradead.org/mtd-utils.git; the tools are recv_image and serve_image. usage: recv_image usage: serve_image [] A $ dd if=3D/dev/urandom of=3Dtestfile bs=3D131072 count=3D50 A $ ./serve_image ff0f::114 12345 testfile 131072 85 Inter-packet delay (avg): 32858=C2=B5s Transmit rate: 85 KiB/s Checking CRC....85a0d369 Checking block CRCS.... 50/50 Image size 6400 KiB (0x00640000). 50 blocks at 47 pkts/block Estimated transmit time per cycle: 77s Sending data block 004e0000 packet 15/70 (85 KiB/s) =20 B $ ./recv_image ff0f::114 12345 foo MEMGETINFO: Inappropriate ioctl for device Receive to file bar with (assumed) erasesize 131072 Received 750/2350 (31%) in 25s @82KiB/s, 6 lost (0%), 0 dup/xs =20 You can use it unicast too, and/or with Legacy IP instead of IPv6. If your AP sends all multicast at 1Mb/s, then 85 KiB/s is about all you'll get. If you can configure the Basic Rate set not to include the slower speeds, or if you can change the multicast rate (which could actually be _any_ rate in the Basic Rate set), then you can go faster. I find it works quite nicely at 24Mb/s. --=20 dwmw2 - To unsubscribe from this list: send the line "unsubscribe linux-wireles= s" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html