[dpdk-dev] [PATCH] app/testpmd: adds mlockall() to fix pages

Eelco Chaudron echaudro at redhat.com
Thu Sep 14 09:22:38 CEST 2017

On 13/09/17 11:39, Thomas Monjalon wrote:
> 12/09/2017 15:08, Eelco Chaudron:
>> Call the mlockall() function, to attempt to lock all of its process
>> memory into physical RAM, and preventing the kernel from paging any
>> of its memory to disk.
>> When using testpmd for performance testing, depending on the code path
>> taken, we see a couple of page faults in a row. These faults effect
>> the overall drop-rate of testpmd. On Linux the mlockall() call will
>> prefault all the pages of testpmd (and the DPDK libraries if linked
>> dynamically), even without LD_BIND_NOW.
> Does it work on FreeBSD?
I do not have a FreeBSD setup, but from the documentation I've read the 
call is supported by FreeBSD.
If some one has a working setup, please give this patch a quick try.
> Is there any drawback?
> Do we need to add an option for it?
The only drawback I can think of is that with this change memory 
phyiscal memory is consumed as pages are pre-loaded.
For testpmd (just loaded not doing anything) this is 2MB vs 35MB of 
memory used. I do not think this yields an extra option.

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