From owner-freebsd-hackers Mon Oct 8 9:45:56 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from mail5.speakeasy.net (mail5.speakeasy.net [216.254.0.205]) by hub.freebsd.org (Postfix) with ESMTP id 3283937B407 for ; Mon, 8 Oct 2001 09:45:50 -0700 (PDT) Received: (qmail 78653 invoked from network); 8 Oct 2001 16:45:49 -0000 Received: from unknown (HELO laptop.baldwin.cx) ([64.81.54.73]) (envelope-sender ) by mail5.speakeasy.net (qmail-ldap-1.03) with SMTP for ; 8 Oct 2001 16:45:49 -0000 Message-ID: X-Mailer: XFMail 1.4.0 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <16e.20f7124.28f3296e@aol.com> Date: Mon, 08 Oct 2001 09:45:21 -0700 (PDT) From: John Baldwin To: Bsdguru@aol.com Subject: RE: splx() overhead. Cc: hackers@freebsd.org Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On 08-Oct-01 Bsdguru@aol.com wrote: > In doing some kernel profiling analysis it seems that splx is taking up big > chunks of time. That's becaause splx() can result in interrupts blocked during an spl() getting a chance to run, including soft interrrupts such as softclock and the network software interrupts. Note that splx itself is quick, it is the releasing of interrupts which is expensive, which will only happen on the "outside" splx() if you have nested spl's. > The mbuf macros call splimp()..splx() explicitly..are they required at > interrupt time? Is there a higher performance way of protecting the necessary > code? Not really. > B -- John Baldwin -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message