[ovs-dev] Hugepages allocation
kapil20084 at gmail.com
Mon Oct 3 12:41:34 UTC 2016
Thanks for the info. Helpful!
On Mon, Oct 3, 2016 at 5:41 PM, Bodireddy, Bhanuprakash <
bhanuprakash.bodireddy at intel.com> wrote:
> >-----Original Message-----
> >From: dev [mailto:dev-bounces at openvswitch.org] On Behalf Of Kapil
> >Sent: Monday, October 3, 2016 12:07 PM
> >To: dev at openvswitch.org; discuss at openvswitch.org
> >Subject: [ovs-dev] Hugepages allocation
> >1. in INSTALL.DPDK.md, huge page size is recommended as 2MB pages.
> >i remember seeing some reference to use 1GB huge pages. is there any
> >noticeable performance improvement in using 1G hugepages vs 2M pages ?
> We did some benchmarks and found that there isn't any significant
> performance difference using 2MB hugepages over 1GB pages.
> >2. is there a way to allocate 1G hugepages using sysctl. Default hugepage
> >is 2M and i didn't find any way to modify it using sysctl. is grub config
> the only
> >way to allocate 1GB pages ?
> Yes, for this one has to build kernel with CONFIG_CMA. In case the kernel
> is built with this, one can allocate hugepages at run time as below
> echo N > /sys/devices/system/node/nodeX/hugepages/hugepages-
> >3. Is there any difference in allocating huge pages run time vs
> >persistent(/etc/sysctl.d/hugepages.conf) ? will the hugepages allocated
> >runtime will be fragmented or something?
> The only advantage of allocating hugepages at boot time is you are sure to
> get the requested pages as the memory isn't fragmented.
> if memory is too fragmented the chances are that fewer pages would be
> allocated by kernel than requested.
> >dev mailing list
> >dev at openvswitch.org
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