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Re: Why systemtap loses events and what can be done about it?
Brad Peters <bpeters@linux.vnet.ibm.com> writes:
> [...] as interrupts are disabled whenever a probe is run, only one can run
> at any given time on a per cpu basis. [...]
We would also block reentrant probes, so disabling interrupts is only
a means rather than the cause of atomic probe execution.
> The only solution, AFIK, is to optimize/minimize your probe code.
Running it with "-t" (timing) will give some measurements about how
much time the probe handlers are taking, and thus can help guide
optimization.
> This does not eliminate the problem, however. Given enough probe
> hits, you will still see contention.
Yes, that is the nature of the beast.
- FChE