Messages in this thread | | | Date | Thu, 17 Feb 2005 21:11:45 +0100 | From | Ingo Molnar <> | Subject | Re: Oops with oprofile + RT preempt 2.6.11-rc2-RT-V0.7.37-01 |
| |
* Lee Revell <rlrevell@joe-job.com> wrote:
> 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.
yes - most of the overhead can be disabled, but not all. 1% CPU time might sound alot but when compared against 10% (or more) tracing overehad it's small. The least overhead comes from disabling tracing in the .config.
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/
| |