Re: [mosquitto-dev] [RSMB] Strange memory behavior

[Mohamed HAMZAOUI <requinham@xxxxxxxxx>]

Hi Roger,

I didn't undertand your remark. I think writev() and WSASend() is used
to write from several buffers to one socket. In fact, I am talking
about sending the same data to several sockets without copy this data
in process memory like Eclipse Mosquitto do.
Can you explain to me if I misunderstood you.

Regards,
Mohamed


On Tue, Oct 18, 2016 at 4:14 PM, Roger Light <roger@xxxxxxxxxx> wrote:
> Hi Mohamed,
>
> Of course that is possible. That does mean writing the outgoing
> message in multiple calls to write() though. When I've done this is
> the past it has resulted in the message being split over multiple tcp
> packets even when not necessary, so a single byte payload for example
> is suddenly a whole lot less bandwidth efficient.
>
> The solution is to use writev(), but this isn't portable. The roughly
> equivalent Windows call is WSASend(). This just hasn't been looked at
> yet.
>
> Cheers,
>
> Roger
>
>
>
> On Tue, Oct 18, 2016 at 1:22 PM, Mohamed HAMZAOUI <requinham@xxxxxxxxx> wrote:
>> Hi Roger,
>>
>> I just checkout master git on https://github.com/eclipse/mosquitto and
>> when testing the last working version, I detect this behavior :
>> 1- At starting the broker allocate 37240 KB of virtual memory and 4756
>> of resident memory (in the last version just 4340 virtual and 1360
>> resident)
>> 2- When transferring my message of 100 MB, the memory peak is about
>> 242048 for one publisher and one subscriber and about 550 MB for one
>> publisher and 4 subscriber. It's not bad compared to latest version
>> but I think there are a means to marshal message from only one
>> instance in memory ?
>>
>> Regards,
>> Mohamed
>>
>>
>>
>> On Tue, Oct 18, 2016 at 12:54 PM, Roger Light <roger@xxxxxxxxxx> wrote:
>>> Hi Mohamed,
>>>
>>>> I don't understand exceeding 300 MB to transfer 100MB message size
>>>> between one publisher and one subscriber ! Then I tried to test RSMB
>>>> code but more problems.
>>>
>>> This is down to some unnecessary copying of the payload which is
>>> already changed in the development branch.
>>>
>>> Cheers,
>>>
>>> Roger
>>> _______________________________________________
>>> mosquitto-dev mailing list
>>> mosquitto-dev@xxxxxxxxxxx
>>> To change your delivery options, retrieve your password, or unsubscribe from this list, visit
>>> https://dev.eclipse.org/mailman/listinfo/mosquitto-dev
>> _______________________________________________
>> mosquitto-dev mailing list
>> mosquitto-dev@xxxxxxxxxxx
>> To change your delivery options, retrieve your password, or unsubscribe from this list, visit
>> https://dev.eclipse.org/mailman/listinfo/mosquitto-dev
> _______________________________________________
> mosquitto-dev mailing list
> mosquitto-dev@xxxxxxxxxxx
> To change your delivery options, retrieve your password, or unsubscribe from this list, visit
> https://dev.eclipse.org/mailman/listinfo/mosquitto-dev