> On Jan. 14, 2016, 9:03 a.m., Benjamin Bannier wrote:
> > Was the decision to optimize here driven by profiling?
> >
> > Given the proposed implementation I wonder if this was worth the risk. I
> > can only see this being called for single element `queues` of `Events`
> > which should not be too expensive to copy, especially given how little we
> > worry about e.g., creating temporary `strings` elsewhere.
My main motivation for making the change was driven by the semantics of how the
callback function processes the data here:
```
void received(queue<Event> events)
{
while (!events.empty()) {
Event event = events.front();
events.pop();
switch (event.type()) {
}
}
```
Since, the callback function always has to invoke a `.pop()`. The argument
`queue<Event> events` has to be passed on by value. So, we were effectively,
copying the same object twice.
Also, after performing the `move`, we were invoking the assignment operation
that did not have a precondition associated with it for `std::queue` and hence
seemed safe to make the change. But, the queue can at best have a few events
(at max). In most cases being `== 1` as you pointed out, except for the cases
where the callback function takes some time and we queued more events from the
master in the interim.
I am discarding this for now. We can always revisit this later.
- Anand
-----------------------------------------------------------
This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/42273/#review114441
-----------------------------------------------------------
On Jan. 13, 2016, 11:06 p.m., Anand Mazumdar wrote:
>
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://reviews.apache.org/r/42273/
> -----------------------------------------------------------
>
> (Updated Jan. 13, 2016, 11:06 p.m.)
>
>
> Review request for mesos and Vinod Kone.
>
>
> Repository: mesos
>
>
> Description
> -------
>
> This trivial fix invokes `std::move` on the `queue` object to not perform a
> copy before invoking the `async(..)` call.
>
>
> Diffs
> -----
>
> src/scheduler/scheduler.cpp a17872b46ec600e0fae6c43247ccb63f5ee55ac0
>
> Diff: https://reviews.apache.org/r/42273/diff/
>
>
> Testing
> -------
>
> make check
>
>
> Thanks,
>
> Anand Mazumdar
>
>
