On 03/14/2015 10:48 AM, Bob Copeland wrote:
On Sat, Mar 14, 2015 at 09:14:14AM -0700, Ben Greear wrote:
It can change with every packet based on rate-control logic, right?
You said you wanted to go from index to bitrate -- the index changes,
but not the rate<->index mapping.
The index means different things based on legacy, HT, VHT. You need index
+ flags to determine the actual rate for each packet.
I am fine with hard-coding in user-space the correlation of legacy index
to rates.
The array that is currently sent to user-space is the rates that rate-ctrl
determines should be used for transmit (and re-transmit), as far as I can tell.
And, it seems unlikely to me that an extra 16 bytes or so would make a
great deal of difference. Using hash tables instead of linear walks
and other things would likely improve performance more?
Last time I tested with perf, memcpy dominated everything -- I've been
thinking about having a mode where just headers are sent to userspace
to avoid some of that.
I need full pkt in user-space, but at least for some use-cases your idea
may be a nice improvement.
With hundreds of virtual radios and network devices, hashing the lookup of
radios should be a big win. I'll work on that someday soon most likely.
Thanks,
Ben
--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com
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