![]() | |||||||||||
Messages in this thread |
Con Kolivas wrote: > On Friday 26 May 2006 14:20, Peter Williams wrote: >> These patches implement CPU usage rate limits for tasks. > > Nice :) Thanks. > >> Although the rlimit mechanism already has a CPU usage limit (RLIMIT_CPU) >> it is a total usage limit and therefore (to my mind) not very useful. >> These patches provide an alternative whereby the (recent) average CPU >> usage rate of a task can be limited to a (per task) specified proportion >> of a single CPU's capacity. The limits are specified in parts per >> thousand and come in two varieties -- hard and soft. > > Why 1000? Probably a hang over from a version where the units were proportion of a whole machine. Percentage doesn't work very well if there are more than 1 CPU in that case (especially if there are more than 100 CPUs :-)). But it's also useful to have the extra range if your trying to cap processes (or users) from outside the scheduler using these primitives. > I doubt that degree of accuracy is possible in cpu accounting and > accuracy or even required. To me it would seem to make more sense to just be > a percentage. > It's not meant to imply accuracy :-). The main issue is avoiding overflow when doing the multiplications during the comparisons. Peter -- Peter Williams pwil3058@bigpond.net.au "Learning, n. The kind of ignorance distinguishing the studious." -- Ambrose Bierce - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||
| Last update: 2006-05-27 03:30 [from the cache] ©2003-2008 | |||||||||||