Linus Torvalds wrote:
On Thu, 24 Nov 2005, Chris Wedgwood wrote:
CPUs in embedded the space could outnumber desktops & servers greatly
(cell phones, access pointers, routers, media players, etc). Most of
these will be UP for some time.
That's not entirely clear either.
There are definite advantages to SMP even in the embedded space - or, to
put it more strongly: _especially_ in the embedded space.
I would argue that there is no "the embedded space," but rather a set of
embedded spaces with various needs. Having worked doing industrial
control for three years and lunched with IC folks another decade, I'm
fairly sure that consumer goods are very different from real industrial
control, a realtime items (multimedia) are different than phones and
PDAs. Until the phone gets "swear at it" slow, features like voice
recognition are more important than doing voice to number lookup in 20ms
instead of 400ms. Cost and battery life matter a lot too, while the
media and IC markets are already attached to expensive stuff, so the
computer is is smaller fraction of the cost.
None of the cellphone manufacturers seem to be in the least interested in
doing a "phone only" solution. They can already do that cheaply, they
can't make much money off it, and they are all interested in features. And
it really _is_ more power-efficient to have, say, a dual-core 200MHz chip
than it is to have a single-core 300MHz one.
Now, sometimes those SMP systems will actually be used as "tightly coupled
UP", where one of the CPU's is just basically a DSP. And from a power
efficiency standpoint, having specialized hardware (and thus _A_MP rather
than SMP) is obviously better, but in complex tasks - and communication
tends to be that - general-purpose is often desirable enough that people
will take the inefficiencies of a GP CPU over a fixed-function specialized
DSP-kind of environment.
But SMP is absolutely _not_ unusual in embedded. It's been there for years
already, and it's clearly moving downwards there too.
Absolutely true, but that dual core 200 MHz chip probably draws more
power than a 200 MHz uni, etc. So there will probably be uni
applications for the forseeable future, any benefit in uni performance
will be useful.
--
-bill davidsen ([email protected])
"The secret to procrastination is to put things off until the
last possible moment - but no longer" -me
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
