Eric Dumazet
94c7eb54c4
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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.