Hi Anatoly, You mentioned that the maximum size of mempool is limited. Can you tell what is the limit and where is it specified?
Regards, Siddarth On Tue, Feb 4, 2020 at 5:27 PM siddarth rai <sid...@gmail.com> wrote: > Hi, > > Thanks for the clarification > > Regards, > Siddarth > > On Tue, Feb 4, 2020 at 4:43 PM Burakov, Anatoly <anatoly.bura...@intel.com> > wrote: > >> On 04-Feb-20 10:55 AM, siddarth rai wrote: >> > Hi Anatoly, >> > >> > I don't need a secondary process. >> >> I understand that you don't, however that doesn't negate the fact that >> the codepath expects that you do. >> >> > >> > I tried out Julien's suggestion and set the param 'RTE_MAX_MEM_MB' >> value >> > to 8192 (the original value was over 500K). This works as a cap. >> > The virtual size dropped down to less than 8G. So this seems to be >> > working for me. >> > >> > I have a few queries/concerns though. >> > Is it safe to reduce the RTE_MAX_MEM_MB to such a low value ? Can I >> > reduce it further ? What will be the impact of doing so ? Will it limit >> > the maximum size of mbuf pool which I create ? >> >> It depends on your use case. The maximum size of mempool is limited as >> is, the better question is where to place that limit. In my experience, >> testpmd mempools are typically around 400MB per socket, so an 8G upper >> limit should not interfere with testpmd very much. However, depending on >> what else is there and what kind of allocations you may do, it may have >> other effects. >> >> Currently, the size of each internal per-NUMA node, per-page size page >> table is dictated by three constraints: maximum amount of memory per >> page table (so that we don't attempt to reserve thousands of 1G pages), >> maximum number of pages per page table (so that we aren't left with a >> few hundred megabytes' worth of 2M pages), and total maximum amount of >> memory (which places an upper limit on the sum of all page tables' >> memory amounts). >> >> You have lowered the latter to 8G which means that, depending on your >> system configuration, you will have at most 2G to 4G per page table. It >> is not possible to limit it further (for example, skip reservation on >> certain nodes or certain page sizes). Whether it will have an effect on >> your actual workload will depend on your use case. >> >> > >> > Regards, >> > Siddarth >> > >> > On Tue, Feb 4, 2020 at 3:53 PM Burakov, Anatoly >> > <anatoly.bura...@intel.com <mailto:anatoly.bura...@intel.com>> wrote: >> > >> > On 30-Jan-20 8:51 AM, David Marchand wrote: >> > > On Thu, Jan 30, 2020 at 8:48 AM siddarth rai <sid...@gmail.com >> > <mailto:sid...@gmail.com>> wrote: >> > >> I have been using DPDK 19.08 and I notice the process VSZ is >> huge. >> > >> >> > >> I tried running the test PMD. It takes 64G VSZ and if I use the >> > >> '--in-memory' option it takes up to 188G. >> > >> >> > >> Is there anyway to disable allocation of such huge VSZ in DPDK ? >> > > >> > > *Disclaimer* I don't know the arcanes of the mem subsystem. >> > > >> > > I suppose this is due to the memory allocator in dpdk that >> reserves >> > > unused virtual space (for memory hotplug + multiprocess). >> > >> > Yes, that's correct. In order to guarantee memory reservation >> > succeeding >> > at all times, we need to reserve all possible memory in advance. >> > Otherwise we may end up in a situation where primary process has >> > allocated a page, but the secondary can't map it because the address >> > space is already occupied by something else. >> > >> > > >> > > If this is the case, maybe we could do something to enhance the >> > > situation for applications that won't care about multiprocess. >> > > Like inform dpdk that the application won't use multiprocess and >> skip >> > > those reservations. >> > >> > You're welcome to try this, but i assure you, avoiding these >> > reservations is a lot of work, because you'd be adding a yet another >> > path to an already overly complex allocator :) >> > >> > > >> > > Or another idea would be to limit those reservations to what is >> > passed >> > > via --socket-limit. >> > > >> > > Anatoly? >> > >> > I have a patchset in the works that does this and was planning to >> > submit >> > it to 19.08, but things got in the way and it's still sitting there >> > collecting bit rot. This may be reason enough to resurrect it and >> > finish >> > it up :) >> > >> > > >> > > >> > > >> > > -- >> > > David Marchand >> > > >> > >> > >> > -- >> > Thanks, >> > Anatoly >> > >> >> >> -- >> Thanks, >> Anatoly >> >
