On 6/9/2020 1:46 PM, Burakov, Anatoly wrote: > On 08-Jun-20 12:03 PM, Francesco wrote: >> Hi all, >> I upgraded an old DPDK-based app which was using DPDK 17.11 to latest DPDK >> 20.05 and I noticed that if I look at "top" I see that the VIRT memory >> taken by my application is now 256.1GB while before it was <1GB. >> >> I've seen this same behavior with also "testpmd" example... is this a known >> issue with latest DPDK versions? >> Can I tweak some setting to have VIRT memory usage more or less similar to >> RSS ? >> >> I forgot to add I'm working on Linux, Centos7 >> >> Thanks, >> Francesco Montorsi >> > > There was a discussion on this not too long ago, but i can't seem to > find it for some reason.
Can it be "Big spike in DPDK VSZ" ? http://inbox.dpdk.org/dev/CAGxAMwD6Wtfi=C2Txwjfk0zhFvRzeqBu7mFfE8ayh=eji2a...@mail.gmail.com/#t > Anyway, long story short, that's not a bug, > that's by design. > > Since 18.11 (or 18.05 to be precise), there is a new memory subsystem in > DPDK that allows growing and shrinking DPDK memory usage at runtime. > That means, you can start with zero hugepages preallocated, and then > allocate as you go, letting the memory subsystem decide how much memory > you need. > > The catch is that all of this hugepage memory is allocated into > somewhere, some virtual address space. And *that* address space is > preallocated at startup, to allow for secondary processes to duplicate > primary process's address space exactly, and allow dynamic allocation of > *shared* memory at runtime. > > This memory will show up in top et al. but the truth is, it's zero cost, > because it's anonymous memory. It isn't actually taking up any RAM. It > will show up in dumps (20.05 has already fixed that issue, and the fixes > will probably be backported to stable, including 18.11), so unless you > have a very specific problem, i don't think that's anything you should > be concerned about. >
