compose MemorySegments

[Chris Vest]

On Fri, 11 Jun 2021 at 15:53, Pedro Lamarão <pedro.lamarao at prodist.com.br>
wrote:

> Em sex., 11 de jun. de 2021 às 00:17, leerho <leerho at gmail.com> escreveu:
>
> > This is an interesting problem and a difficult one to do efficiently
> > without copies or additional allocations. I think the OS does similar
> > tricks when it maps virtual memory addresses into CPU caches or main
> > memory.  To the user's program it appears as a contiguous memory space
> but
> > in reality could be broken into many separate physical chunks.  I'm sure
> > there are some ways one could do this in C++, but probably not as
> efficient
> > as the OS could do it.
> >
>
> Virtual memory is "accelerated" by the hardware's MMU;
> that would be a very hard performance target to replicate in userspace.
>
The tricks we'd need to play (if we can assume aligned, whole-page chunks,
anyway) are available to us in user-space via the mmap(2) system call.
The RUMA paper shows how you can build dynamic data structures on top of
this:
http://www.vldb.org/pvldb/vol9/p768-schuhknecht.pdf


> --
> Pedro Lamarão
> https://www.prodist.com.br
> Securing Critical Systems
> Tel: +55 11 4380-6585
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