From 7b1b2b60c63f070e0dfbe072ccaae13168b38d01 Mon Sep 17 00:00:00 2001 From: Adrian Moreno Date: Thu, 4 Jul 2024 10:56:55 +0200 Subject: net: psample: allow using rate as probability 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. Reviewed-by: Aaron Conole Acked-by: Eelco Chaudron Reviewed-by: Ido Schimmel Signed-off-by: Adrian Moreno Link: https://patch.msgid.link/20240704085710.353845-5-amorenoz@redhat.com Signed-off-by: Jakub Kicinski --- net/psample/psample.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'net/psample') diff --git a/net/psample/psample.c b/net/psample/psample.c index 1c76f3e48dcd..f48b5b9cd409 100644 --- a/net/psample/psample.c +++ b/net/psample/psample.c @@ -497,6 +497,9 @@ void psample_sample_packet(struct psample_group *group, struct sk_buff *skb, md->user_cookie)) goto error; + if (md->rate_as_probability) + nla_put_flag(skb, PSAMPLE_ATTR_SAMPLE_PROBABILITY); + genlmsg_end(nl_skb, data); genlmsg_multicast_netns(&psample_nl_family, group->net, nl_skb, 0, PSAMPLE_NL_MCGRP_SAMPLE, GFP_ATOMIC); -- cgit v1.2.3