On Mon, Jun 17, 2024 at 06:32:14AM +0000, Adrián Moreno wrote: > On Fri, Jun 14, 2024 at 05:11:30PM GMT, Simon Horman wrote: > > On Mon, Jun 03, 2024 at 08:56:38PM +0200, Adrian Moreno wrote: > > > Although not explicitly documented in the psample module itself, the > > > definition of PSAMPLE_ATTR_SAMPLE_RATE seems inherited from act_sample. > > > > > > Quoting tc-sample(8): > > > "RATE of 100 will lead to an average of one sampled packet out of every > > > 100 observed." > > > > > > With this semantics, the rates that we can express with an unsigned > > > 32-bits number are very unevenly distributed and concentrated towards > > > "sampling few packets". > > > For example, we can express a probability of 2.32E-8% but we > > > cannot express anything between 100% and 50%. > > > > > > For sampling applications that are capable of sampling a decent > > > amount of packets, this sampling rate semantics is not very useful. > > > > > > Add a new flag to the uAPI that indicates that the sampling rate is > > > expressed in scaled probability, this is: > > > - 0 is 0% probability, no packets get sampled. > > > - U32_MAX is 100% probability, all packets get sampled. > > > > > > Signed-off-by: Adrian Moreno <[email protected]> > > > > Hi Adrian, > > > > Would it be possible to add appropriate documentation for > > rate - both the original ratio variant, and the new probability > > variant - somewhere? > > > > Hi Simon, thanks for the suggestion. Would the uapi header be a good > place for such documentation?
Hi Adrian, I didn't look closely, but that does sound like a good place to me. _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
