Messages in this thread | | | Subject | Re: Oops with oprofile + RT preempt 2.6.11-rc2-RT-V0.7.37-01 | From | Lee Revell <> | Date | Thu, 17 Feb 2005 15:05:26 -0500 |
| |
On Sun, 2005-02-13 at 14:30 +0100, Ingo Molnar wrote: > * Philippe Elie <phil.el@wanadoo.fr> wrote: > > > oprofile_ops.cpu_type == NULL, this has been fixed 3 weeks ago, can > > you retry with -rc4 ? > > i've uploaded an -rc4 port of the -RT tree half an hour ago (-39-00). >
Thanks, -rc4 did fix the bug.
I noticed profiling the kernel with PREEMPT_DESKTOP that mcount and __mcount add quite a bit of overhead. Something like .5% CPU each. Sorry, I didn't save the oprofile output.
So, disable CONFIG_MCOUNT if you want minimal overhead from the RT patches. IIRC it was previously stated that the latency tracing overhead could be mostly avoided by disabling it at runtime.
Lee
- 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/
| |