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Jiri Olsa says:
====================
hi,
sending 2 fixes to fix kernel support for loading
trampoline programs in bcc/bpftrace and allow to
unwind through trampoline/dispatcher.
Original rfc post [1].
Speedup output of perf bench while running klockstat.py
on kprobes vs trampolines:
Without:
$ perf bench sched messaging -l 50000
...
Total time: 18.571 [sec]
With current kprobe tracing:
$ perf bench sched messaging -l 50000
...
Total time: 183.395 [sec]
With kfunc tracing:
$ perf bench sched messaging -l 50000
...
Total time: 39.773 [sec]
v4 changes:
- rebased on latest bpf-next/master
- removed image tree mutex and use trampoline_mutex instead
- checking directly for string pointer in patch 1 [Alexei]
- skipped helpers patches, as they are no longer needed [Alexei]
v3 changes:
- added ack from John Fastabend for patch 1
- move out is_bpf_image_address from is_bpf_text_address call [David]
v2 changes:
- make the unwind work for dispatcher as well
- added test for allowed trampolines count
- used raw tp pt_regs nest-arrays for trampoline helpers
thanks,
jirka
[1] https://lore.kernel.org/netdev/20191229143740.29143-1-jolsa@kernel.org/
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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.