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authorJesper Dangaard Brouer <brouer@redhat.com>2017-08-29 16:37:56 +0200
committerDavid S. Miller <davem@davemloft.net>2017-08-29 10:51:29 -0700
commitf5836ca5e9867fa6ab88cadb9873af56d9ceb589 (patch)
tree81b8317a3d986fb176b2df280d946bd250e4ad1a /include/trace
parentb06337dfdb16bc3f668326b6a618c472c671182a (diff)
xdp: separate xdp_redirect tracepoint in error case
There is a need to separate the xdp_redirect tracepoint into two tracepoints, for separating the error case from the normal forward case. Due to the extreme speeds XDP is operating at, loading a tracepoint have a measurable impact. Single core XDP REDIRECT (ethtool tuned rx-usecs 25) can do 13.7 Mpps forwarding, but loading a simple bpf_prog at the tracepoint (with a return 0) reduce perf to 10.2 Mpps (CPU E5-1650 v4 @ 3.60GHz, driver: ixgbe) The overhead of loading a bpf-based tracepoint can be calculated to cost 25 nanosec ((1/13782002-1/10267937)*10^9 = -24.83 ns). Using perf record on the tracepoint event, with a non-matching --filter expression, the overhead is much larger. Performance drops to 8.3 Mpps, cost 48 nanosec ((1/13782002-1/8312497)*10^9 = -47.74)) Having a separate tracepoint for err cases, which should be less frequent, allow running a continuous monitor for errors while not affecting the redirect forward performance (this have also been verified by measurements). Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/trace')
-rw-r--r--include/trace/events/xdp.h22
1 files changed, 18 insertions, 4 deletions
diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h
index 89eba564e199..1eebad55ebd4 100644
--- a/include/trace/events/xdp.h
+++ b/include/trace/events/xdp.h
@@ -94,11 +94,25 @@ DEFINE_EVENT(xdp_redirect_template, xdp_redirect,
TP_ARGS(dev, xdp, to_ifindex, err, map, map_index)
);
-#define _trace_xdp_redirect(dev, xdp, to, err) \
- trace_xdp_redirect(dev, xdp, to, err, NULL, 0);
+DEFINE_EVENT(xdp_redirect_template, xdp_redirect_err,
+ TP_PROTO(const struct net_device *dev,
+ const struct bpf_prog *xdp,
+ int to_ifindex, int err,
+ const struct bpf_map *map, u32 map_index),
+ TP_ARGS(dev, xdp, to_ifindex, err, map, map_index)
+);
+
+#define _trace_xdp_redirect(dev, xdp, to) \
+ trace_xdp_redirect(dev, xdp, to, 0, NULL, 0);
+
+#define _trace_xdp_redirect_err(dev, xdp, to, err) \
+ trace_xdp_redirect_err(dev, xdp, to, err, NULL, 0);
+
+#define trace_xdp_redirect_map(dev, xdp, fwd, map, idx) \
+ trace_xdp_redirect(dev, xdp, fwd ? fwd->ifindex : 0, 0, map, idx);
-#define trace_xdp_redirect_map(dev, xdp, fwd, err, map, idx) \
- trace_xdp_redirect(dev, xdp, fwd ? fwd->ifindex : 0, err, map, idx);
+#define trace_xdp_redirect_map_err(dev, xdp, fwd, map, idx, err) \
+ trace_xdp_redirect_err(dev, xdp, fwd ? fwd->ifindex : 0, err, map, idx);
#endif /* _TRACE_XDP_H */