Hi Demitry,

Thank you for your reply.

Tried many things with no success.

I have tried 1G hugepage size x 2 pages and the VIRT value went up from 66.0 G to 128G.

I used DPDK 17.11 with 1024 Hugepages of size 2MB and did not see VIRT more than 5.5G.

With 1G hugepage size:

[root@vstreamOR9-160 ~]# ./dpdk-hugepages.py --show

Node Pages Size Total

0    2     1Gb    2Gb

Hugepages mounted on /dev/hugepages /mnt/huge

You can see the 16 G and 32 G mappings with 1G hugepage size.  Any additional mmap we do in our application fails for “OUT OF MEMORY (12)”

pmap -d <appPID>

0000000100035000       4 rw-s- 0000000000000000 000:00019 fbarray_memseg-1048576k-0-0

0000000140000000 1048576 rw-s- 0000000000000000 000:00027 rtemap_0

0000000180000000 1048576 rw-s- 0000000000000000 000:00027 rtemap_1

00000001c0000000 31457280 ----- 0000000000000000 000:00000   [ anon ]

0000000940000000       4 rw-s- 0000000000000000 000:00019 fbarray_memseg-1048576k-0-1

0000000980000000 33554432 ----- 0000000000000000 000:00000   [ anon ]

0000001180000000     388 rw-s- 0000000000000000 000:00019 fbarray_memseg-2048k-0-0

0000001180200000 16777216 ----- 0000000000000000 000:00000   [ anon ]

0000001580200000     388 rw-s- 0000000000000000 000:00019 fbarray_memseg-2048k-0-1

0000001580400000 16777216 ----- 0000000000000000 000:00000   [ anon ]

0000001980400000     388 rw-s- 0000000000000000 000:00019 fbarray_memseg-2048k-0-2

0000001980600000 16777216 ----- 0000000000000000 000:00000   [ anon ]

0000001d80600000     388 rw-s- 0000000000000000 000:00019 fbarray_memseg-2048k-0-3

0000001d80800000 16777216 ----- 0000000000000000 000:00000   [ anon ]

I tried dpdk_testpmd (# ./dpdk-testpmd -l 0-3  -n 1 -- -i --portmask=0x01) on my VM and the VIRT memory jumps to 66 GB with 2MB hugepage size and 1024 huge pages.

I also tried adding –single-file-segments in the EAL init argument.

When you say VIRT memory is not important then what would you suggest I focus on to determine the resource hog that DPDK 22.11 injects in our application?

Is there too many mmaps done by DPDK in 22.11?

Thanks,

Ed

From: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
Sent: Sunday, November 5, 2023 1:23 PM
To: Lombardo, Ed <Ed.Lombardo@netscout.com>
Cc: users <users@dpdk.org>
Subject: Re: DPDK 22.11.2 requires too much VIRT memory, how to reduce

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Hi Ed, 

DPDK indeed reserves a large amount of virtual address space at startup. This does not prevent DPDK from running on low-memory systems, since this reservation does not consume physical memory. So the large figure in VIRT is not an issue. Hugepages are mapped on demand. Each mapped hugepage consunes a file descriptor. If you use 2MB hugepages, the number of open files can exhaust the limit easily. If you don't want to increase it, please see: https://doc.dpdk.org/guides/prog_guide/env_abstraction_layer.html#segment-file-descriptors