a6a69db4b6
Move the rdtsc() function so it can be reusued. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1406035081-14301-24-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
48 lines
899 B
C
48 lines
899 B
C
#include <stdbool.h>
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#include <errno.h>
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#include <linux/perf_event.h>
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#include "../../perf.h"
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#include <linux/types.h>
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#include "../../util/debug.h"
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#include "../../util/tsc.h"
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#include "tsc.h"
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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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{
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bool cap_user_time_zero;
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u32 seq;
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int i = 0;
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while (1) {
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seq = pc->lock;
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rmb();
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tc->time_mult = pc->time_mult;
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tc->time_shift = pc->time_shift;
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tc->time_zero = pc->time_zero;
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cap_user_time_zero = pc->cap_user_time_zero;
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rmb();
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if (pc->lock == seq && !(seq & 1))
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break;
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if (++i > 10000) {
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pr_debug("failed to get perf_event_mmap_page lock\n");
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return -EINVAL;
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}
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}
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if (!cap_user_time_zero)
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return -EOPNOTSUPP;
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return 0;
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}
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u64 rdtsc(void)
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{
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unsigned int low, high;
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asm volatile("rdtsc" : "=a" (low), "=d" (high));
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return low | ((u64)high) << 32;
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}
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