From owner-freebsd-bugs@FreeBSD.ORG Sat Dec 20 05:20:03 2008 Return-Path: Delivered-To: freebsd-bugs@hub.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 26B801065670 for ; Sat, 20 Dec 2008 05:20:03 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id 1450C8FC13 for ; Sat, 20 Dec 2008 05:20:03 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1]) by freefall.freebsd.org (8.14.3/8.14.3) with ESMTP id mBK5K2jT019513 for ; Sat, 20 Dec 2008 05:20:02 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.14.3/8.14.3/Submit) id mBK5K26Z019512; Sat, 20 Dec 2008 05:20:02 GMT (envelope-from gnats) Date: Sat, 20 Dec 2008 05:20:02 GMT Message-Id: <200812200520.mBK5K26Z019512@freefall.freebsd.org> To: freebsd-bugs@FreeBSD.org From: Dieter Cc: Subject: Re: kern/118093: firewire bus reset hogs CPU, causing data to be lost X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Dieter List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 20 Dec 2008 05:20:03 -0000 The following reply was made to PR kern/118093; it has been noted by GNATS. From: Dieter To: freebsd-firewire@freebsd.org, bug-followup@freebsd.org Cc: Subject: Re: kern/118093: firewire bus reset hogs CPU, causing data to be lost Date: Fri, 19 Dec 2008 11:02:21 +0000 Here are the results of two more experiments: I tried to verify what spl the firewire code is at when calling printf(9) by adding the following block into fwohci.c just before one of the printfs. { #include #include intrmask_t debug_spl; /* __uint32_t */ intrmask_t debug_spl_high; intrmask_t debug_spl_tty; intrmask_t debug_spl_fw; intrmask_t debug_spl_0; intrmask_t debug_spl_net; debug_spl = splhigh(); debug_spl_high = spltty(); debug_spl_tty = splfw(); debug_spl_fw = splnet(); debug_spl_net = splhigh(); spl0(); /* void */ debug_spl_0 = splhigh(); splx(debug_spl); printf("fwohci_intr_core(): spl = 0x%x\n splhigh=0x%x spltty=0x%x splfw=0x%x splnet=0x%x spl0=0x%x\n", debug_spl, debug_spl_high, debug_spl_tty, debug_spl_fw, debug_spl_net, debug_spl_0); } But my results appear bogus: fwohci_intr_core(): spl = 0x0 splhigh=0x0 spltty=0x0 splfw=0x0 splnet=0x0 spl0=0x0 I have examined my code and the spl(9) man page several times but I can't find what is wrong. Any clues? -------------------------------------------------------- To isolate the effects of printf(9) from the firewire bus reset, I picked a trivial system call (chown(2)) and added some printf(9) calls. Calling chown several times and monitoring with systat -vmstat gives: 1098 interrupts on the console IRQ 93.1%Sys 6.7%Intr 0.2%User 0.0%Nice 0.0%Idle This did NOT interfere with Ethernet. So printf(9) interferes with Ethernet when called from the firewire driver, but not when called from a vanilla system call. -------------------------------------------------------- sio0: <16550A-compatible COM port> port 0x3f8-0x3ff irq 4 flags 0x10 on acpi0 sio0: type 16550A, console sio0: [FILTER] What does [FILTER] mean? I don't see an explanation on the sio man page.