diff options
| author | Jesper Dangaard Brouer <brouer@redhat.com> | 2017-08-29 17:37:56 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-08-29 20:51:29 +0300 |
| commit | f5836ca5e9867fa6ab88cadb9873af56d9ceb589 (patch) | |
| tree | 81b8317a3d986fb176b2df280d946bd250e4ad1a /include/trace | |
| parent | b06337dfdb16bc3f668326b6a618c472c671182a (diff) | |
| download | linux-f5836ca5e9867fa6ab88cadb9873af56d9ceb589.tar.xz | |
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.h | 22 |
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 */ |