From: Adam Jensen <hanzer@riseup.net>
Subject: Re: What is the current language profile for concurrent, multi-core, safety-critical, hard real-time systems?
Date: Tue, 1 Aug 2017 01:45:22 -0000 (UTC)
Date: 2017-08-01T01:45:22+00:00 [thread overview]
Message-ID: <olomfi$5kg$1@dont-email.me> (raw)
In-Reply-To: umjvncldvg2v535dlt77l7dmh7gahi0bn5@4ax.com
On Mon, 31 Jul 2017 20:54:08 -0400, Dennis Lee Bieber wrote:
> On Tue, 1 Aug 2017 00:25:18 -0000 (UTC), Adam Jensen <hanzer@riseup.net>
> declaimed the following:
>
>
>>What is the current Ada language profile for concurrent, multi-core,
>>safety-critical, hard real-time systems?
>
> As soon as you say "multi-core" you enter the realm of
experimental
> science. For example -- in the four years I spent at GE Aviation,
> multi-core processors used in flight management software would be run
> with all but one core shutdown.
>
> Reason: there has not been enough experience/study of how multiple
> cores/cache/etc. affect hard real-time latency (how can you evaluate
> WCET for a process on core-A when you don't have control of what happens
> on core-B, which could cause cache line flushing, etc. affecting the
> timing of core-A)
>
> What multi-core processors I saw being used in development were
for
> non-safety critical functions -- data logging type operations, wherein
> loss of the logging processor wouldn't affect the flight management
> system; only reducing the post-flight analysis capabilities should there
> be anomalous flight operations.
That's interesting, thanks. I've been looking at the ARM Cortex-R8[1]
which seems like it might address some of these issues in its hardware
architecture.
[1]: https://developer.arm.com/products/processors/cortex-r/cortex-r8
I suppose that mapping an Ada run-time system onto that specific hardware
might require a significant investment.
But more simply, this web page <http://www.ada2012.org/> says: "Ravenscar
for multiprocessor systems adapts a safe and widely used tasking profile
to modern architectures". Doesn't that seem to suggest that there exists
an Ada-2012 Ravenscar profile for multi-core systems? Is that mostly hype
or hokum?
next prev parent reply other threads:[~2017-08-01 1:45 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-01 0:25 What is the current language profile for concurrent, multi-core, safety-critical, hard real-time systems? Adam Jensen
2017-08-01 0:54 ` Dennis Lee Bieber
2017-08-01 1:45 ` Adam Jensen [this message]
2017-08-01 4:19 ` Dennis Lee Bieber
2017-08-01 7:12 ` Dmitry A. Kazakov
2017-08-01 8:38 ` Jacob Sparre Andersen
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