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Add a new --quiet option to 'perf stat'. This is useful with 'perf stat record' to write the data only to the perf.data file, which can lower measurement overhead because the data doesn't need to be formatted. On my 4C desktop: % time ./perf stat record -e $(python -c 'print ",".join(["cycles"]*1000)') -a -I 1000 sleep 5 ... real 0m5.377s user 0m0.238s sys 0m0.452s % time ./perf stat record --quiet -e $(python -c 'print ",".join(["cycles"]*1000)') -a -I 1000 sleep 5 real 0m5.452s user 0m0.183s sys 0m0.423s In this example it cuts the user time by 20%. On systems with more cores the savings are higher. Signed-off-by: Andi Kleen <andi@firstfloor.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Link: http://lore.kernel.org/lkml/20201027002737.30942-1-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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.