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Re: [Discuss-gnuradio] Using USRP from multiple applications simultaneou
Re: [Discuss-gnuradio] Using USRP from multiple applications simultaneously
Sun, 1 May 2005 23:25:56 +0200
mutt-ng 1.5.8-r168i (Debian)
mh, yet another comment on zerocopy. I wish there was a reply to my
question on the usb-multiple-interface issue ;)
On Sun, May 01, 2005 at 10:25:15PM +0200, Stephane Fillod wrote:
> "Premature optimization is the root of all evil", Donald Knuth.
Mh, that's my common mistake. I always over-optimize in the beginning,
and software takes ages until it's actually released. Still I can't
> Before implementing, verify that this is the biggest spot of
> optimization. You can use great tools like OProfile for that purpose.
It just hurts to see waste valuable cpu time, memory bandwidth and cache
pollution in a case that at least appears to be very easily optimizied.
I was probably spending man-months to see how to optimize kernel
networking code, where we can't do all those neat optimizations that
seem perfectly possible with USB.
> Do you(or somebody else) know a more clever kernel/user interface
> with zero-copy for the USB subsystem?
there is none. That's what my point was about. Implementing mmap() on
the filedescriptor in usbdevfs.
> I guess now we're more in functional development, but it's always
> open on who has spare time ;-)
I don't have the time, but the problem seems interesting enough to find
some time for it.
- Harald Welte <address@hidden> http://gnumonks.org/
"Privacy in residential applications is a desirable marketing option."
(ETSI EN 300 175-7 Ch. A6)
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