When a packet flood hits one or more UDP sockets, many cpus
have to update sk->sk_drops.
This slows down other cpus, because currently
sk_drops is in sock_write_rx group.
Add a socket_drop_counters structure to udp sockets.
Using dedicated cache lines to hold drop counters
makes sure that consumers no longer suffer from
false sharing if/when producers only change sk->sk_drops.
This adds 128 bytes per UDP socket.
Tested with the following stress test, sending about 11 Mpps
to a dual socket AMD EPYC 7B13 64-Core.
super_netperf 20 -t UDP_STREAM -H DUT -l10 -- -n -P,1000 -m 120
Note: due to socket lookup, only one UDP socket is receiving
packets on DUT.
Then measure receiver (DUT) behavior. We can see both
consumer and BH handlers can process more packets per second.
Before:
nstat -n ; sleep 1 ; nstat | grep Udp
Udp6InDatagrams 615091 0.0
Udp6InErrors 3904277 0.0
Udp6RcvbufErrors 3904277 0.0
After:
nstat -n ; sleep 1 ; nstat | grep Udp
Udp6InDatagrams 816281 0.0
Udp6InErrors 7497093 0.0
Udp6RcvbufErrors 7497093 0.0
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250826125031.1578842-5-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Drop bpf_iter.h header which uses vmlinux.h but re-defines a bunch of
iterator structures and some of BPF constants for use in BPF iterator
selftests.
None of that is necessary when fresh vmlinux.h header is generated for
vmlinux image that matches latest selftests. So drop ugly hacks and have
a nice plain vmlinux.h usage everywhere.
We could do the same with all the kfunc __ksym redefinitions, but that
has dependency on very fresh pahole, so I'm not addressing that here.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20241029203919.1948941-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
These macros are convenient wrappers around the bpf_seq_printf and
bpf_snprintf helpers. They are currently provided by bpf_tracing.h which
targets low level tracing primitives. bpf_helpers.h is a better fit.
The __bpf_narg and __bpf_apply are needed in both files and provided
twice. __bpf_empty isn't used anywhere and is removed from bpf_tracing.h
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210526164643.2881368-1-revest@chromium.org
A handful of samples and selftests fail to build on s390, because
after commit 0ebeea8ca8 ("bpf: Restrict bpf_probe_read{, str}()
only to archs where they work") bpf_probe_read is not available
anymore.
Fix by using bpf_probe_read_kernel.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200720114806.88823-1-iii@linux.ibm.com
Eric Dumazet