From owner-cvs-all Sat Mar 30 22:49:43 2002 Delivered-To: cvs-all@freebsd.org Received: from freefall.freebsd.org (freefall.FreeBSD.org [216.136.204.21]) by hub.freebsd.org (Postfix) with ESMTP id DEA8137B41C; Sat, 30 Mar 2002 22:49:38 -0800 (PST) Received: (from bde@localhost) by freefall.freebsd.org (8.11.6/8.11.6) id g2V6ncg06578; Sat, 30 Mar 2002 22:49:38 -0800 (PST) (envelope-from bde) Message-Id: <200203310649.g2V6ncg06578@freefall.freebsd.org> From: Bruce Evans Date: Sat, 30 Mar 2002 22:49:38 -0800 (PST) To: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/dev/sio sio.c X-FreeBSD-CVS-Branch: HEAD Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG bde 2002/03/30 22:49:38 PST Modified files: sys/dev/sio sio.c Log: Hacks for measuring interrupt latency. Interrupt latency can be measured accurately for periodic interrupts provided the interrupts don't need to be serviced very quickly to keep their period almost constant. sio output interrupts have this property (interrupt service can be delayed for up to 1 character time without the period changing). This is non-optional and undocumented so that it can be added and removed easily. It has no significant effect unless it is enabled by hacking on a variable using a debugger. Hardclock and statclock interrupts would work even better for this, at least on i386's, provided their interrupt handlers are fast (as they are in -current but not in -stable or in my version of -current). Revision Changes Path 1.370 +42 -2 src/sys/dev/sio/sio.c To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message