perf record: Check conflict between '--timestamp-filename' option and pipe mode before recording
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: ecfd7a9c ("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.comSigned-off-by: Namhyung Kim <namhyung@kernel.org>
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