On 2018-05-15 12:30, Johannes Berg wrote:
On Tue, 2018-05-15 at 10:47 +0530, Sriram R wrote:
This patchset adds support for the collection and propagating of
per-rate, per-station rx statistics when enabled by a userspace
application.
These statistics can be useful in understanding the quality of
communication with our peers and in evaluating how different peers
are communicating in different MCS/BW/NSS during different time
periods and environment.
So ... I know that you're aware of my rate statistics collection code
(at least you should be, I showed it to Jouni), so I think you should
state why that approach isn't suitable.
Hi Johannes,
I really liked your approach of publishing the rate statistics only
when subscribers exist and to push the data when we hit some limits (pkt
count nearing UINT16_MAX or when 'escape' entries gets used).
But, I wanted to avoid,
1. Static indexing and memory allocation based on MCS count((8x3)24
entries for HT and (10x3)30 for VHT within allocated 36 entries) so that
it's scalable.
2. Remote chance of dropping a stats(Though it does not have much
impact)
And to allow,
1. A 'station dump' kind of interface to dump the complete collected
stats instead of returning only current snapshot of the stats within
kernel.
In particular, I don't like the idea that you implement here of
allowing
unresponsive (or dead) userspace to let the data pile up indefinitely.
I
think we should be sending it out upon reaching a threshold to limit
the
memory consumption in the kernel more reliably.
I agree with you that this does not allow deterministic memory
allocation within kernel (when rate stats are enabled).
I'll revisit this approach to address your concern and to allow a data
aggregator kind of usersapce application to collect info and provide
complete stats.
Also, do you feel it would be good to have both ,i.e complete stats
collection within kernel(this approach) and dump+clear of stats on
reaching threshold(your approach) and have one of these two modes
selected based on the requirement.
Thanks,
Sriram.R
johannes
