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The perf mmap'ed buffer contains the flag 'cap_user_time_short' and two extra fields 'time_cycles' and 'time_mask', perf tool needs to know them for handling the counter wrapping case. This patch is to reads out the relevant parameters from the head of the first mmap'ed page and stores into the structure 'perf_tsc_conversion', if the flag 'cap_user_time_short' has been set, it will firstly calibrate cycle value for timestamp calculation. Committer testing: Before/after: # perf test tsc 70: Convert perf time to TSC : Ok # # perf test -v tsc 70: Convert perf time to TSC : --- start --- test child forked, pid 11059 mmap size 528384B 1st event perf time 996384576521 tsc 3850532906613 rdtsc time 996384578455 tsc 3850532913950 2nd event perf time 996384578845 tsc 3850532915428 test child finished with 0 ---- end ---- Convert perf time to TSC: Ok # Signed-off-by: Leo Yan <leo.yan@linaro.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Gustavo A. R. Silva <gustavoars@kernel.org> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: John Garry <john.garry@huawei.com> Cc: Kemeng Shi <shikemeng@huawei.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Nick Gasson <nick.gasson@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Remi Bernon <rbernon@codeweavers.com> Cc: Stephane Eranian <eranian@google.com> Cc: Steve Maclean <steve.maclean@microsoft.com> Cc: Will Deacon <will@kernel.org> Cc: Zou Wei <zou_wei@huawei.com> Cc: linux-arm-kernel@lists.infradead.org Link: http://lore.kernel.org/lkml/20200914115311.2201-4-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
27 lines
584 B
C
27 lines
584 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __PERF_TSC_H
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#define __PERF_TSC_H
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#include <linux/types.h>
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struct perf_tsc_conversion {
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u16 time_shift;
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u32 time_mult;
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u64 time_zero;
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u64 time_cycles;
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u64 time_mask;
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bool cap_user_time_zero;
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bool cap_user_time_short;
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};
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struct perf_event_mmap_page;
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int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc,
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struct perf_tsc_conversion *tc);
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u64 perf_time_to_tsc(u64 ns, struct perf_tsc_conversion *tc);
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u64 tsc_to_perf_time(u64 cyc, struct perf_tsc_conversion *tc);
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u64 rdtsc(void);
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#endif // __PERF_TSC_H
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