On 04/06/2012 09:51 AM, Felix Fietkau wrote:
On 2012-04-04 5:13 PM, Ben Greear wrote:
On 04/04/2012 05:01 AM, Felix Fietkau wrote:
+ * @rx_beacons: No. of beacons received.
+ * @rx_frags: No. of rx-fragements received.
Why should the driver keep track of those last two?
Well, for instance, I often see around 5Mbps of total rx bytes
(as counted by the NIC), but much less transmitted. And this is
with stations sending to stations.
I was trying to figure out where the extra packets come from. It
seems beacons is a lot of it so it seemed worth counting. And maybe
fragments count towards that too since there would be more overhead???
As for rx-frags, just seemed useful to know how many frags
were received. My understanding is that this is like receiving
1/2 of a packet at a time...so if we wanted to know how many
real packets the NIC received, we'd need to take frags v/s non-frags
into account. The current logic that counts 'all-packets' for
the rx path is counting individual fragments, I think.
At least for beacons, as long as they are always passed up
the stack, I can count them in the mac80211 layer instead if
you prefer.
When you only need the packet type based counters for debugging stuff,
why not just create a monitor mode interface and count in user space?
I think that would make more sense, since these counters are irrelevant
for most users, and avoiding unnecessary work in the rx path is useful
for performance reasons.
I always want to be calculating stats. I will poll many of them in user-space
every few seconds to generate reports. It is way easier and more efficient to get
some numbers out of ethtool (or have a user cat a debugfs file)
than it is to set up a sniffer and parse it's output.
If you want me to create another compile-time option for the
extra stats, I can do that?
Thanks,
Ben
--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com
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