[dpdk-dev] Please stop using iopl() in DPDK

Thomas Gleixner tglx at linutronix.de
Fri Oct 25 22:43:54 CEST 2019


On Fri, 25 Oct 2019, Stephen Hemminger wrote:
> On Thu, 24 Oct 2019 21:45:56 -0700
> Andy Lutomirski <luto at kernel.org> wrote:
> > 3. Use ioperm() instead of iopl().
> 
> Ioperm has the wrong thread semantics. All DPDK applications have
> multiple threads and the initialization logic needs to work even
> if the thread is started later; threads can also be started by
> the user application.
> 
> Iopl applies to whole process so this is not an issue.

No. iopl is also per thread and not per process. That has been that way
forever. The man page is blantantly wrong.

Both iopl and ioperm are inherited on fork.
 
Thanks,

	tglx


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