On Sun, Sep 4, 2016 at 2:07 AM, Neeraj Sharma <[email protected]> wrote: > On Tue, Aug 2, 2016 at 7:37 PM, Antti Kantee <[email protected]> wrote: >> On 29/07/16 16:53, Neeraj Sharma wrote: >>> >>> Is there a hard setting somewhere regarding the system RAM? I assumed >>> that rumprun would automatically detect the RAM configuration from >>> qemu correctly but I notice that the amount of RAM reported is >>> considerably less than the one configured in qemu command-line >>> options. >>> >>> Notice below that 256 MB is configured in qemu, while just 123 MB is >>> reported in console log. Is there something which I am missing here? >> >> >> It's not an inconsistency so much as a slightly misleading print. That's the >> amount of memory available to the rump kernel. It gets half of the guest >> memory. The application (plus bmk) gets the other half. Last year during >> spargelzeit while sitting outside Schloss Grunwald I scribbled a design into >> my notebook for the memory division to be dynamic. However, I never had a >> use case for fully implementing that scheme, and apparently nobody else was >> inclined to improved that area either, so here we are now. >> > > I just couldn't dig deeper on this one although it's an important > point when running applications on Rumprun unikernel.
I was half asleep while posting this message and hence probably caused confusion (at least to me when I was reading it myself in the morning). I meant that I could not spend time looking for stuff in the code to gain a better understanding, although any pointers to half written doc/notes or code will be of great help. > Having said > that, is memory always divided in half between the kernel and the > application? If so, then it implies that the application cannot use > more than half of the provisioned memory at any time. Basically just going by the understanding that only half of provisioned memory is available to application is a source of concern, or maybe I missed something. > I have not spent much time thinking about but given my limited > understanding of rump kernel understanding it will be great to have > some kind of note upon the memory architecture and how much goes where > and used where kind of stuff. > I believe a scan of your notes or something of that sort supplemented by pointers (or reference) to code sections will help. Basically I am looking at ways and means to understand the memory requirement while running Erlang/Elixir applications on Rumprun and hence came the requirement to understand the memory partitioning and usage. This will help in better configuring the system so as to think about using the system for not-for-fun projects (or production). Thanks, Neeraj
