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authorAdrian Moreno <amorenoz@redhat.com>2024-07-04 10:56:55 +0200
committerJakub Kicinski <kuba@kernel.org>2024-07-05 17:45:47 -0700
commit7b1b2b60c63f070e0dfbe072ccaae13168b38d01 (patch)
tree68420e693c20aacac7c60dd3407418c29126787b /net
parentc35d86a23029f1186e3c7a65df7c38b762fb0434 (diff)
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 <aconole@redhat.com> Acked-by: Eelco Chaudron <echaudro@redhat.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Signed-off-by: Adrian Moreno <amorenoz@redhat.com> Link: https://patch.msgid.link/20240704085710.353845-5-amorenoz@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/psample/psample.c3
1 files changed, 3 insertions, 0 deletions
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);