e55c8abaad
[ Upstream commit 02f9b50e04812782fd006ed21c6da1c5e3e373da ]
In pipe mode, no need to switch perf data output, therefore,
'--timestamp-filename' option should not take effect.
Check the conflict before recording and output WARNING.
In this case, the check pipe mode in perf_data__switch() can be removed.
Before:
# perf record --timestamp-filename -o- perf test -w noploop | perf report -i- --percent-limit=1
# To display the perf.data header info, please use --header/--header-only options.
#
[ perf record: Woken up 1 times to write data ]
[ perf record: Dump -.2024011812110182 ]
#
# Total Lost Samples: 0
#
# Samples: 4K of event 'cycles:P'
# Event count (approx.): 2176784359
#
# Overhead Command Shared Object Symbol
# ........ ....... .................... ......................................
#
97.83% perf perf [.] noploop
#
# (Tip: Print event counts in CSV format with: perf stat -x,)
#
After:
# perf record --timestamp-filename -o- perf test -w noploop | perf report -i- --percent-limit=1
WARNING: --timestamp-filename option is not available in pipe mode.
# To display the perf.data header info, please use --header/--header-only options.
#
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.000 MB - ]
#
# Total Lost Samples: 0
#
# Samples: 4K of event 'cycles:P'
# Event count (approx.): 2185575421
#
# Overhead Command Shared Object Symbol
# ........ ....... ..................... .............................................
#
97.75% perf perf [.] noploop
#
# (Tip: Profiling branch (mis)predictions with: perf record -b / perf report)
#
Fixes: ecfd7a9c044e ("perf record: Add '--timestamp-filename' option to append timestamp to output file name")
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240119040304.3708522-3-yangjihong1@huawei.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Sasha Levin <sashal@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.