[lttng-dev] HugePages shared memory support in LLTng

[Yiteng Guo]

(Forgot to cc mailing list in the previous email)

Hi Jonathan,

On Tue, Jul 23, 2019 at 4:27 PM Jonathan Rajotte-Julien
<jonathan.rajotte-julien at efficios.com> wrote:
>
> CC'ing the mailing list back.
>
> On Tue, Jul 23, 2019 at 03:58:09PM -0400, Yiteng Guo wrote:
> > Hi Jonathan,
> >
> > Thank you for the patch! It is really helpful.
>
> Were you able to observe a positive impact?
>
> This is something we might be interested in upstreaming if we have good
> feedback.

Yes, page faults disappeared and I didn't get those periodic overheads anymore.

And I also solved the problem that hugepages are not closed correctly
in my patch. It is my fault that I forgot to close the mmap pointer. I
updated the patch here:
https://github.com/lttng/lttng-ust/compare/master...guoyiteng:hugepages
The current prefault solution works well for me and I will use that
for now. In my opinion, using hugepages could further reduce the TLB
misses, but that involved more changes in source codes than the
prefault solution.

Best,
Yiteng