6e6eda44b9
Add 2 tracepoints to monitor the tcp/udp traffic of per process and per cgroup. Regarding monitoring the tcp/udp traffic of each process, there are two existing solutions, the first one is https://www.atoptool.nl/netatop.php. The second is via kprobe/kretprobe. Netatop solution is implemented by registering the hook function at the hook point provided by the netfilter framework. These hook functions may be in the soft interrupt context and cannot directly obtain the pid. Some data structures are added to bind packets and processes. For example, struct taskinfobucket, struct taskinfo ... Every time the process sends and receives packets it needs multiple hashmaps,resulting in low performance and it has the problem fo inaccurate tcp/udp traffic statistics(for example: multiple threads share sockets). We can obtain the information with kretprobe, but as we know, kprobe gets the result by trappig in an exception, which loses performance compared to tracepoint. We compared the performance of tracepoints with the above two methods, and the results are as follows: ab -n 1000000 -c 1000 -r http://127.0.0.1/index.html without trace: Time per request: 39.660 [ms] (mean) Time per request: 0.040 [ms] (mean, across all concurrent requests) netatop: Time per request: 50.717 [ms] (mean) Time per request: 0.051 [ms] (mean, across all concurrent requests) kr: Time per request: 43.168 [ms] (mean) Time per request: 0.043 [ms] (mean, across all concurrent requests) tracepoint: Time per request: 41.004 [ms] (mean) Time per request: 0.041 [ms] (mean, across all concurrent requests It can be seen that tracepoint has better performance. Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com> Signed-off-by: Xiongchun Duan <duanxiongchun@bytedance.com> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> 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.