Return-path: Received: from mx1.redhat.com ([209.132.183.28]:21562 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751506Ab1K2LoR (ORCPT ); Tue, 29 Nov 2011 06:44:17 -0500 Date: Tue, 29 Nov 2011 12:46:04 +0100 From: Stanislaw Gruszka To: Robert Hancock Cc: linux-kernel , linux-wireless , users@rt2x00.serialmonkey.com Subject: Re: [rt2x00-users] Poor performance and lockup with rt2800usb and Asus USB-N13 adapter Message-ID: <20111129114603.GB7299@redhat.com> (sfid-20111129_124437_300183_E6518A7A) References: <4ED43A5C.9000102@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <4ED43A5C.9000102@gmail.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Mon, Nov 28, 2011 at 07:50:20PM -0600, Robert Hancock wrote: > I recently got an Asus USB-N13 USB Wireless-N adapter which > apparently uses a Ralink RT3072 chip. I'm using it with an Asus > RT-N16 access point running TomatoUSB. When running Windows the > performance is reasonable (about 80 Mbps in both directions). > However under Fedora 16 (currently kernel 3.1.2) the performance is > abysmal (10 Mbps or less with lots of packet loss). I'll post some > debug information below. rt2800usb needs fixing. I'm able to reproduce these performance problems locally. They are quite hard to debug, and need some experiments. But I hope I will provide patches soon or leter. > While debugging this I also noticed that doing an rmmod on rt2800usb > with the adapter plugged in locks up the machine and then spews out > soft lockup stack traces on the console. I was only able to capture > it off the screen with a camera, but it basically is: > > rt2x00usb_work_rxdone > process_one_work > worker_thread > kthread > kernel_thread_helper Another thing to investigate. Can yo try to reproduce that with CONFIG_DEBUG_OBJECTS=y CONFIG_DEBUG_OBJECTS_FREE=y CONFIG_DEBUG_OBJECTS_TIMERS=y CONFIG_DEBUG_OBJECTS_WORK=y CONFIG_DEBUG_OBJECTS_RCU_HEAD=y CONFIG_DEBUG_SPINLOCK=y CONFIG_DEBUG_MUTEXES=y CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y CONFIG_LOCKDEP=y and see if these options print some aditional message when rmmod. Thanks Stanislaw