Messages in this thread | | | Date | Fri, 08 Jun 2007 19:13:52 +0200 | From | Martin Peschke <> | Subject | Re: [RFC] [Patch 4/4] lock contention tracking slimmed down |
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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.
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