[ovs-dev] [PATCH v2] Make 100 percents packets sampled when sampling rate is 1.

Wenyu Zhang wenyuz at vmware.com
Wed Aug 5 10:11:12 UTC 2015

> On Aug 4, 2015, at 12:17 PM, Ben Pfaff <blp at nicira.com> wrote:
> On Tue, Aug 04, 2015 at 04:05:58AM +0000, Wenyu Zhang wrote:
>> In ipfix and sflow, the sampling rate can be set as 1, which means
>> 100%.  And in order to make 100% packets sampled, I work out a patch
>> in datapath, which is for review on net-next.  And the same change
>> seems need to be added into lib/odp-execute.c too. Do you mean that it
>> is not necessary here?
> I mean that we should modify the IPFIX and sFlow sampling code so that
> in the 0% and 100% sample rates cases it doesn't generate a sample
> action; there isn't any value in it.
> This situation is a little different from the kernel situation, since we
> know exactly what actions can be fed to the userspace datapath in
> odp-execute.c, since the actions that it executes are generated by
> another part of the same source tree.  The kernel datapath, however,
> should be equally capable of handling actions from sources other than
> the Open vSwitch userspace.

It is  OK that sample action shouldn’t be generated when the sampling rate is 0%.
But I wonder why we shouldn’t generate sample action when the sampling rate is 100%. It should happen in kernel datapth.
Or you means that the 100% sampling rate case won’t happen in the userspace datapath?

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