[dpdk-dev] Huge ring allocation

[Wiles, Keith]

Regards,
Keith

> On Aug 25, 2016, at 1:05 AM, Gregory Etelson <gregory at weka.io> wrote:
> 
> Hello,
> 
> I have a DPDK process that creates pktmbuf pool with 2_000_000 objects
> In CentOS 6.x x86-64, ring size of this pool is 16MB
> 8 2MB hugepages required to hold such ring.

Have you try to use 1G huge pages, is that an option?

> In some cases, hugepages are too fragmented and there are no 8 contiguous hugepages for the ring.
> As the result, the process has enough hugepages memory, but ring allocation fails.

Another issue sometimes is huge pages are allocated after the system has booted, which means you need to assign the number of huge pages very early in the boot process. This means adding a line in the sysctrl.conf file instead of poking the value later.

vm.nr_hugepages=XXX

> I use a workaround for these cases and create a ring with standard OS allocation routines.
> Is there another way I could use unclaimed dpdk hugepages for that allocation ?
> 
> Regards,
> Gregory