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8af19d66b9
Using .st_ctime clobbers the timestamp information in perf report header
whenever any operation is done with the file. Even tar-ing and untar-ing
the perf.data file (which preserves the file last modification timestamp)
doesn't prevent that:
[Michael@Diego tmp]$ ls -l perf.data
-> -rw-------. 1 Michael Michael 169888 Dec 2 15:23 perf.data
[Michael@Diego tmp]$ perf report --header-only
# ========
-> # captured on : Mon Dec 2 15:23:42 2019
[...]
[Michael@Diego tmp]$ tar c perf.data | xz > perf.data.tar.xz
[Michael@Diego tmp]$ mkdir aaa
[Michael@Diego tmp]$ cd aaa
[Michael@Diego aaa]$ xzcat ../perf.data.tar.xz | tar x
[Michael@Diego aaa]$ ls -l -a
total 172
drwxrwxr-x. 2 Michael Michael 23 Jan 14 11:26 .
drwxrwxr-x. 6 Michael Michael 4096 Jan 14 11:26 ..
-> -rw-------. 1 Michael Michael 169888 Dec 2 15:23 perf.data
[Michael@Diego aaa]$ perf report --header-only
# ========
-> # captured on : Tue Jan 14 11:26:16 2020
[...]
When using .st_mtime instead, correct information is printed:
[Michael@Diego aaa]$ ~/acme/tools/perf/perf report --header-only
# ========
-> # captured on : Mon Dec 2 15:23:42 2019
[...]
Signed-off-by: Michael Petlan <mpetlan@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
LPU-Reference: 20200114104236.31555-1-mpetlan@redhat.com
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.