From owner-lockmeter@oss.sgi.com Tue Aug 21 07:35:01 2001 Received: (from majordomo@localhost) by oss.sgi.com (8.11.2/8.11.3) id f7LEZ1122698 for lockmeter-outgoing; Tue, 21 Aug 2001 07:35:01 -0700 Received: from ureach.com (mail.ureach.com [63.150.151.36]) by oss.sgi.com (8.11.2/8.11.3) with SMTP id f7LEYx922695 for ; Tue, 21 Aug 2001 07:34:59 -0700 Received: from www20.ureach.com (IDENT:root@www20.ureach.com [172.16.2.48]) by ureach.com (8.9.1/8.8.5) with ESMTP id KAA15030 for ; Tue, 21 Aug 2001 10:34:53 -0400 Received: (from nobody@localhost) by www20.ureach.com (8.9.3/8.9.1) id KAA23810; Tue, 21 Aug 2001 10:34:53 -0400 Date: Tue, 21 Aug 2001 10:34:53 -0400 Message-Id: <200108211434.KAA23810@www20.ureach.com> To: lockmeter@oss.sgi.com From: Kapish K Reply-to: Subject: query related to spinlock metering Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-vsuite-type: e Sender: owner-lockmeter@oss.sgi.com Precedence: bulk Hello, We have been facing some problems with some kernel defects and in the process we felt it might be worthwhile to try some wrapper around the spinlock code to see if it might be getting called wrongly or released wrongly. So, what we would like to is just a wrapper around the spinlock code to do some preliminary checks to make sure the lock is held before releasing it or along similar lines. Is this lockmeter from sgi similar in performance and is it lightweight? would it make sense for us to try this out rather than put down our own? but we are trying this to debug a smp related race problem.. so, if the performance impact of this is quite high, we might not even hit the problem and hence would not want to use it... so, if you can inform me about how much of an overhead this would be and its design in terms of whether it does check for wrong calls to spinlock ( lock or unlock ), it would eb of help to us. TIA ________________________________________________ Get your own "800" number Voicemail, fax, email, and a lot more http://www.ureach.com/reg/tag From owner-lockmeter@oss.sgi.com Tue Aug 21 11:35:31 2001 Received: (from majordomo@localhost) by oss.sgi.com (8.11.2/8.11.3) id f7LIZV727399 for lockmeter-outgoing; Tue, 21 Aug 2001 11:35:31 -0700 Received: from zok.sgi.com (zok.sgi.com [204.94.215.101]) by oss.sgi.com (8.11.2/8.11.3) with SMTP id f7LIZT927396 for ; Tue, 21 Aug 2001 11:35:29 -0700 Received: from cthulhu.engr.sgi.com (cthulhu.engr.sgi.com [192.26.80.2]) by zok.sgi.com (8.11.4/8.11.4/linux-outbound_gateway-1.0) with ESMTP id f7LIfda03977 for ; Tue, 21 Aug 2001 11:41:39 -0700 Received: from pchawkes (dhcp-163-154-20-203.engr.sgi.com [163.154.20.203]) by cthulhu.engr.sgi.com (SGI-8.9.3/8.9.3) with SMTP id LAA77018; Tue, 21 Aug 2001 11:34:08 -0700 (PDT) Message-ID: <001501c12a6f$fc035da0$cb149aa3@engr.sgi.com> From: "John Hawkes" To: , References: <200108211434.KAA23810@www20.ureach.com> Subject: Re: query related to spinlock metering Date: Tue, 21 Aug 2001 11:34:59 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 Sender: owner-lockmeter@oss.sgi.com Precedence: bulk From: "Kapish K" > We have been facing some problems with some kernel defects > and in the process we felt it might be worthwhile to try some > wrapper around the spinlock code to see if it might be getting > called wrongly or released wrongly. So, what we would like to is > just a wrapper around the spinlock code to do some preliminary > checks to make sure the lock is held before releasing it or > along similar lines. SGI's Lockmeter does not provide any such verification. Lockmeter instruments spinlocks in order to report who locks what spinlocks, how often, for how long, and suffering what wait-times in the event of lock contention. > Is this lockmeter from sgi similar in performance and is it > lightweight? Lockmeter is lighter-weight than some spinlock instumention implementations and heavier-weight than other implementations. Typical system slowdowns are in the 5-15% range. And yes, there is potential for perturbing timing-sensitive locking patterns. If you want to verify that the lock is held when you do an unlock, then you need to roll your own wrapper. John Hawkes hawkes@sgi.com From owner-lockmeter@oss.sgi.com Fri Aug 31 12:21:36 2001 Received: (from majordomo@localhost) by oss.sgi.com (8.11.2/8.11.3) id f7VJLaZ27088 for lockmeter-outgoing; Fri, 31 Aug 2001 12:21:36 -0700 Received: (from hawkes@localhost) by oss.sgi.com (8.11.2/8.11.3) id f7VJLZu27083 for lockmeter@oss.sgi.com; Fri, 31 Aug 2001 12:21:35 -0700 Date: Fri, 31 Aug 2001 12:21:35 -0700 From: John Hawkes Message-Id: <200108311921.f7VJLZu27083@oss.sgi.com> To: lockmeter@oss.sgi.com Subject: lockmeter v1.4.9 available for 2.4.9 kernel Sender: owner-lockmeter@oss.sgi.com Precedence: bulk FYI, the current Lockmeter (version 1.4.9) is now available in the form of a patch against the 2.4.9 kernel: http://oss.sgi.com/projects/lockmeter/download This is the same Lockmeter that is available for 2.4.3, 2.4.4, 2.4.5, and 2.4.6. John Hawkes