Messages in this thread | | | Date | Fri, 6 Jul 2007 19:33:19 +0200 | From | Ingo Molnar <> | Subject | [patch] CFS scheduler, -v19 |
| |
i'm pleased to announce release -v19 of the CFS scheduler patchset.
The rolled-up CFS patch against today's -git kernel, v2.6.22-rc7, v2.6.22-rc6-mm1, v2.6.21.5 or v2.6.20.14 can be downloaded from the usual place:
http://people.redhat.com/mingo/cfs-scheduler/
The biggest user-visible change in -v19 is reworked sleeper fairness: it's similar in behavior to -v18 but works more consistently across nice levels. Fork-happy workloads (like kernel builds) should behave better as well. There are also a handful of speedups: unsigned math, 32-bit speedups, O(1) task pickup, debloating and other micro-optimizations.
Changes since -v18:
- merged the group-scheduling CFS-core changes from Srivatsa Vaddagiri. This makes up for the bulk of the changes in -v19 but has no behavioral impact. The final group-fairness enabler patch is now a small and lean add-on patch to CFS.
- fix the bloat noticed by Andrew. On 32-bit it's now this:
text data bss dec hex filename 24362 3905 24 28291 6e83 sched.o-rc7 33015 2538 20 35573 8af5 sched.o-v18 25805 2426 20 28251 6e5b sched.o-v19
so it's a net win compared to vanilla. On 64-bit it's even better:
text data bss dec hex filename 35732 40314 2168 78214 13186 sched.o.x64-rc7 41397 37642 2168 81207 13d37 sched.o.x64-v18 36132 37410 2168 75710 127be sched.o.x64-v19
( and there's also a +1.5K data win per CPU on x32, which is not shown here. [+3.0K data win per CPU on x64.] )
- good number of core code updates, cleanups and streamlining. (Mike Galbraith, Srivatsa Vaddagiri, Dmitry Adamushko, me.)
- use unsigned data types almost everywhere in CFS. This produces faster and smaller code, and simplifies the logic.
- turn as many 'u64' data types into 'unsigned long' as possible, to reduce the 32-bit footprint and to reduce 64-bit arithmetics.
- replaced the nr_running based 'sleep fairness' logic with a more robust concept. The end-result is similar in behavior to v18, but negative nice levels are handled much better in this scheme.
- speedup: O(1) task pickup by Srivatsa Vaddagiri. [sleep/wakeup is O(log2(nr_running)).] This gives 5-10% better hackbench 100/500 results on a 4-way box.
- fix: set idle->sched_class back to &idle_sched_class in migration_call(). (Dmitry Adamushko)
- cleanup: use an enum for the sched_feature flags. (suggested by Andrew Morton)
- cleanup: turn the priority macros into inlines. (suggested by Andrew Morton)
- (other cleanups suggested by Andrew Morton)
- debug: split out the debugging data into CONFIG_SCHED_DEBUG.
As usual, any sort of feedback, bugreport, fix and suggestion is more than welcome!
Ingo - 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/
| |