Re: Increase DPDK's virtual memory to more than 512 GiB

[Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>]

2025-03-03 15:52 (UTC+0100), Lucas:
> Hi Dmitry,
> 
> Excuse my late reply.
> My system is configured with 1G huge page size upon boot and then later on
> I issue `sysctl -w vm.nr_hugepages=700`
> It appears that the swapping was caused by some daemon that decided to
> start up and allocate quite some memory. I no longer observe this effect.
> I included a FlameGraph (recorded with perf) from program startup that does
> a memory allocation for 500 GB (MBUFS + priv data): mempool allocation
> with 218'531'468 MBUFs.
> Most time is spent in mmap and in memsets.
> 
> Let me know what you think and perhaps if there are ways to improve the
> loading time.

Thanks for the profile, Lucas.

[1] suggests that allocation would take about (500 / 32) * 2.16 = 33.75 sec.
You can run "malloc_perf_autotest" in "dpdk-test" to estimate for your HW.
I don't know any simple and secure way to speed up the kernel part.
Restart can be made faster as [1] suggests, but not the first start.

Try investigating other parts of the profile that take place in user space.

[1]: https://inbox.dpdk.org/dev/20211230143744.3550098-1-dkozlyuk@nvidia.com/