From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <46698E50.6030108@de.ibm.com> Date: Fri, 08 Jun 2007 19:13:52 +0200 From: Martin Peschke MIME-Version: 1.0 Subject: Re: [RFC] [Patch 4/4] lock contention tracking slimmed down References: <1181165656.7133.23.camel@dix> <1181202683.7348.220.camel@twins> In-Reply-To: <1181202683.7348.220.camel@twins> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, jbaron@redhat.com, rostedt@goodmis.org, billh@gnuppy.monkey.org, mingo@elte.hu, linux-s390@vger.kernel.org List-ID: Peter Zijlstra wrote: > On Wed, 2007-06-06 at 23:34 +0200, Martin Peschke wrote: > >> +struct statistic_info lock_stat_info[_LOCK_STAT_NUMBER] = { >> + [LOCK_STAT_CONT] = { >> + .name = "contentions", >> + .x_unit = "instruction_pointer", >> + .y_unit = "occurrence", >> + .defaults = "type=sparse entries=4", >> + .flags = STATISTIC_FLAGS_LABEL, >> + }, >> + [LOCK_STAT_WAIT_READ] = { >> + .name = "wait_read", >> + .x_unit = "nanoseconds", >> + .y_unit = "occurrence", >> + .defaults = "type=utilisation", >> + }, >> + [LOCK_STAT_WAIT_WRITE] = { >> + .name = "wait_write", >> + .x_unit = "nanoseconds", >> + .y_unit = "occurrence", >> + .defaults = "type=utilisation", >> + }, >> + [LOCK_STAT_HOLD_READ] = { >> + .name = "hold_read", >> + .x_unit = "nanoseconds", >> + .y_unit = "occurrence", >> + .defaults = "type=utilisation", >> + }, >> + [LOCK_STAT_HOLD_WRITE] = { >> + .name = "hold_write", >> + .x_unit = "nanoseconds", >> + .y_unit = "occurrence", >> + .defaults = "type=utilisation", >> } >> }; > > You're parsing strings in-kernel to setup data structures? Might be surprising (or revolting?)... but, yes, I do. .defaults reflects the developers opinion on the way of data accumululation that might make most sense in most cases. The current implementation of lib/statistic.c allows users to change setting that we see in .defaults. If one needs to track more than 4 contention points, for example, then they can change this limit by passing "entries=4" to the user interface. So there is some parsing code anyway. Passing default setting in a similar fashion has just been convenient for the developer.