Messages in this thread | | | Date | Sat, 11 Jun 2005 06:32:31 +0200 | From | Ingo Molnar <> | Subject | Re: hackbench: 2.6.12-rc6 vs. 2.6.12-rc6-RT-V0.7.48-06 |
| |
* Esben Nielsen <simlo@phys.au.dk> wrote:
> Depends on the configuration options. If you used the same configs > they should be the same but if you activated PREEMPT_RT it should slow > things down due to the overhead of irq-threading and mutexes instead > of spinlocks - although I am surprised the factor is _that_ big!
one has to make sure the default debug options are disabled. (DEADLOCK_DETECT, PREEMPT_DEBUG, etc.) But even then there will be considerable overhead. Until recently, the overhead used to be even bigger. Note that hackbench is pretty much the worst-case for PREEMPT_RT: lots of locking and scheduling done and we compare the UP kernel to the SMP kernel in essence. (in fact PREEMPT_RT's locking is currently higher overhead than SMP)
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/
| |