Re: [Discuss-gnuradio] FIFO latency

[Andre Puschmann]

On 05/30/2011 03:55 PM, Marcus D. Leech wrote:
> On 30/05/2011 9:51 AM, Alexander Chemeris wrote:
>>
>>> Linux' pipe implementation is known to be quite slow. I would suggest to
>>> use UNIX sockets instead. They should perform much better in terms of
>>> latency and performance.
>> Good idea.
>>
> I'm dubious of such a claim--the core mechanisms between Unix-domain
> sockets and FIFOs are very similar.
> 
> While it's true that it *used* to be the case that pipes/FIFOs were
> handled as disk files, that's no longer true--they
>   just implement ring-buffer objects within the kernel, and Unix-domain
> sockets are also quite similar--in fact, they
>   are likely higher overhead, because they have to go through the
> labyrinthine socket stack, which FIFOs don't.
> 
> I did my part to put together a FIFO test, so if someone wants to do a
> Unix-domain socket benchmark we could settle
>   that question.

There are various papers out there dealing with IPC mechanisms in Linux.
There is at least one [1] that indicates that IPC is performing quite
good. On the other hand, I've seen others claiming the opposite.
Unfortunately, I don't have any recent performance measurements
available personally. But I agree, would be interesting to see some
up-to-date benchmark results.

Cheers,
Andre


[1] http://osnet.cs.binghamton.edu/publications/TR-20070820.pdf