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linux-next/include
Eric Dumazet 94c7eb54c4 random32: add a tracepoint for prandom_u32()
There has been some heat around prandom_u32() lately, and some people
were wondering if there was a simple way to determine how often
it was used, before considering making it maybe 10 times more expensive.

This tracepoint exports the generated pseudo random value.

Tested:

perf list | grep prandom_u32
  random:prandom_u32                                 [Tracepoint event]

perf record -a [-g] [-C1] -e random:prandom_u32 sleep 1
[ perf record: Woken up 0 times to write data ]
[ perf record: Captured and wrote 259.748 MB perf.data (924087 samples) ]

perf report --nochildren
    ...
    97.67%  ksoftirqd/1     [kernel.vmlinux]  [k] prandom_u32
            |
            ---prandom_u32
               prandom_u32
               |
               |--48.86%--tcp_v4_syn_recv_sock
               |          tcp_check_req
               |          tcp_v4_rcv
               |          ...
                --48.81%--tcp_conn_request
                          tcp_v4_conn_request
                          tcp_rcv_state_process
                          ...
perf script

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-13 15:11:14 -07:00
..
acpi ACPI updates for 5.9-rc1 2020-08-03 20:37:22 -07:00
asm-generic Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-08-05 20:13:21 -07:00
clocksource
crypto It's been a busy cycle for documentation - hopefully the busiest for a 2020-08-04 22:47:54 -07:00
drm drm next for 5.9-rc1 2020-08-05 19:50:06 -07:00
dt-bindings drm next for 5.9-rc1 2020-08-05 19:50:06 -07:00
keys It's been a busy cycle for documentation - hopefully the busiest for a 2020-08-04 22:47:54 -07:00
kunit
kvm
linux bitfield.h: don't compile-time validate _val in FIELD_FIT 2020-08-10 12:16:51 -07:00
math-emu
media
memory memory: add Renesas RPC-IF driver 2020-07-01 22:45:14 +01:00
misc
net net: refactor bind_bucket fastreuse into helper 2020-08-11 15:49:08 -07:00
pcmcia
ras
rdma IB/rdmavt: Fix RQ counting issues causing use of an invalid RWQE 2020-07-29 15:54:36 -03:00
scsi
soc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-08-05 20:13:21 -07:00
sound ASoC: Fixes for v5.8 2020-07-17 18:19:02 +02:00
target
trace random32: add a tracepoint for prandom_u32() 2020-08-13 15:11:14 -07:00
uapi bpf: Change uapi for bpf iterator map elements 2020-08-06 16:39:14 -07:00
vdso arm64/vdso: Add time namespace page 2020-07-24 13:15:20 +01:00
video
xen xen: netif.h: add a new extra type for XDP 2020-07-01 15:25:14 -07:00