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Re: "lttng comparison with other tracers" page
Hi -
On Wed, Mar 18, 2009 at 11:14:55AM -0400, Mathieu Desnoyers wrote:
> [...] Have you measured the performance impact of disabling
> interrupts around the probe ?
Yes. Among others, we received reports where oprofile was indicating
more traffic at interrupt-enable time along with somewhat lower
interrupt-handling-latency-related performance.
> Basically, it sounds like you are shipping a car without brakes nor
> air bags simply because it makes the car too heavy and therefore too
> slow. I don't think trading stability and robustness for speed is a
> good tradeoff.
We are doing neither - stability and robustness are not at risk by
this option. You noticed that the system responded with a clean
script stop.
We're starting to see this happen more now only because the kprobes
machinery blocked reentrancy in other ways for us, so we never had to
think hard about what is a good value for the MAXSKIPPED parameter.
- FChE