From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 2 Jun 2001 17:38:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 2 Jun 2001 17:38:04 -0400 Received: from cisco7500-mainGW.gts.cz ([194.213.32.131]:6404 "EHLO bug.ucw.cz") by vger.kernel.org with ESMTP id ; Sat, 2 Jun 2001 17:37:56 -0400 Message-ID: <20010602132200.A186@bug.ucw.cz> Date: Sat, 2 Jun 2001 13:22:00 +0200 From: Pavel Machek To: Linux usb mailing list , kernel list Subject: *BAD* impact of usb on PCI performance Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.93i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! I did some testing how does usb hurt rest of system; and it can be pretty bad. With Acher's uhci, even ifconfig up of usb-to-usb networking device [plusb handled by generic usb-to-usb driver; see -ac series]. does 50% slowdown. When fsbr is being used, systems slows down by 350% (running more than 4 times slower than normally. Ouch). Pavel 2.4.5: 300MHz, no usb at all (compiled out) 0.06user 3.25system 3.30 (0m3.308s) elapsed 100.00%CPU 0.06user 3.25system 3.30 (0m3.307s) elapsed 100.00%CPU 0.03user 3.28system 3.32 (0m3.323s) elapsed 99.61%CPU 2.4.5: 300MHz, usb ifconfig down [acher] 0.05user 3.28system 3.35 (0m3.357s) elapsed 99.18%CPU 0.03user 3.29system 3.31 (0m3.319s) elapsed 100.00%CPU 0.04user 3.29system 3.32 (0m3.325s) elapsed 100.00%CPU 0.01user 3.32system 3.32 (0m3.326s) elapsed 100.00%CPU 2.4.5: 300MHz, usb not plugged [JE] 0.06user 3.24system 3.30 (0m3.303s) elapsed 99.90%CPU 0.06user 3.25system 3.30 (0m3.304s) elapsed 100.00%CPU 0.02user 3.30system 3.33 (0m3.336s) elapsed 99.52%CPU 2.4.5: 300Mhz, plusb loaded and UP [acher] 0.03user 4.93system 4.99 (0m4.993s) elapsed 99.33%CPU 0.02user 4.94system 4.99 (0m4.991s) elapsed 99.37%CPU 0.04user 4.92system 4.99 (0m4.990s) elapsed 99.40%CPU 0.06user 4.90system 4.98 (0m4.985s) elapsed 99.49%CPU 0.04user 4.91system 4.98 (0m4.983s) elapsed 99.33%CPU 0.05user 4.91system 4.98 (0m4.985s) elapsed 99.50%CPU 0.06user 4.90system 4.98 (0m4.989s) elapsed 99.42%CPU 0.06user 4.91system 4.99 (0m4.995s) elapsed 99.49%CPU 2.4.5: 300Mhz, plusb plugged in [JE] 0.03user 3.29system 3.35 (0m3.352s) elapsed 99.05%CPU 0.02user 3.29system 3.34 (0m3.349s) elapsed 98.85%CPU 0.01user 3.30system 3.34 (0m3.349s) elapsed 98.84%CPU 2.4.5: 300Mhz, plusb plugged in and UP [JE] 0.04user 3.29system 3.32 (0m3.327s) elapsed 100.00%CPU 0.02user 3.31system 3.35 (0m3.356s) elapsed 99.23%CPU 0.04user 3.28system 3.35 (0m3.353s) elapsed 99.03%CPU 2.4.5: 300Mhz, plusb loaded and UP, fsbr forced ON [acher] 0.06user 14.39system 14.54 (0m14.542s) elapsed 99.37%CPU 0.03user 14.51system 14.62 (0m14.625s) elapsed 99.42%CPU 0.04user 14.63system 14.79 (0m14.798s) elapsed 99.14%CPU 2.4.5: 300Mhz, plusb loaded and UP, fsbr forced ON [JE] 0.04user 14.87system 14.98 (0m14.986s) elapsed 99.49%CPU 0.06user 14.85system 14.99 (0m14.994s) elapsed 99.43%CPU 0.04user 14.85system 14.98 (0m14.984s) elapsed 99.37%CPU -- I'm pavel@ucw.cz. "In my country we have almost anarchy and I don't care." Panos Katsaloulis describing me w.r.t. patents at discuss@linmodems.org