[PATCH 2/7] wpa_supplicant: Support minimum interval between scan attempts.

Ben Greear greearb
Sat Jul 7 08:42:30 PDT 2012

On 07/07/2012 08:13 AM, Jouni Malinen wrote:
> On Fri, Jul 06, 2012 at 09:52:36AM -0700, greearb at candelatech.com wrote:
>> When running lots of vifs, they can all end up wanting to
>> scan right after the other.  This leaves too little time for
>> useful work to happen.  Allow users to configure a minimum
>> timer interval (in seconds) between scans.  Default is zero,
>> which is current behaviour.
> Is this still needed after the autoscan functionality was added?
> Wouldn't something like autoscan=periodic:30 be usable with more or less
> the same end result?

The problem I saw is that each interface wants to scan...so if you
have 100 virtual stations configured for an AP that doesn't exist,
they are all constantly scanning trying to associate.

Even if the AP exists, if one is trying to associate and the
other 99 trying to scan, association can often time out.

The scan fanout helps, and the scan-on-channel logic in the
kernel helps..but I still found this option useful for
wpa_supplicant as well.

I haven't looked at the autoscan logic, but I think it wouldn't
help the scan-on-startup logic that stations use...


Ben Greear <greearb at candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

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