netdev - Same data to several sockets with just one syscall ?

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Message-ID: <CAGWmfYrGv8NdJQHs6OA=b=ao8=25JUoZAK_i65+GMFX1OyV-fg@mail.gmail.com>
Date:	Fri, 12 Feb 2016 09:53:37 +0100
From:	Claudio Scordino <claudio@...dence.eu.com>
To:	netdev@...r.kernel.org
Subject: Same data to several sockets with just one syscall ?

Hi all.

Suppose I have an application that needs to send the very same data to
several sockets already connected. In this case, the application has
to call the sendto() syscall several times:

      for(...)
               sendto(...)

This makes the application waste time in entering/exiting the kernel
level several times.
Moreover, if I'm not wrong, the kernel is free to execute pending work
(e.g., softirqs) when returning from a syscall, making the application
experience further latency.

I therefore wonder if a mechanism exists for sending the data to
several sockets using just a single syscall. If not, has anybody ever
thought about adding a syscall like the following ?

      sendto-multicast(..., int number_of_sockets, int* const sockets [])

I can't see any obvious reason why such an approach could be wrong.

Many thanks,

               Claudio