mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-05 10:29:37 +00:00
![Leo Yan](/assets/img/avatar_default.png)
The synthesized event TIME_CONV doesn't contain the complete parameters for counters, this will lead to wrong conversion between counter cycles and timestamp. This patch extends event TIME_CONV to record flags 'cap_user_time_zero' which is used to indicate the counter parameters are valid or not, if not will directly return 0 for timestamp calculation. And record the flag 'cap_user_time_short' and its relevant fields 'time_cycles' and 'time_mask' for cycle calibration. Signed-off-by: Leo Yan <leo.yan@linaro.org> 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/20200914115311.2201-5-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
112 lines
2.5 KiB
C
112 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <errno.h>
|
|
|
|
#include <linux/compiler.h>
|
|
#include <linux/perf_event.h>
|
|
#include <linux/stddef.h>
|
|
#include <linux/types.h>
|
|
|
|
#include <asm/barrier.h>
|
|
|
|
#include "event.h"
|
|
#include "synthetic-events.h"
|
|
#include "debug.h"
|
|
#include "tsc.h"
|
|
|
|
u64 perf_time_to_tsc(u64 ns, struct perf_tsc_conversion *tc)
|
|
{
|
|
u64 t, quot, rem;
|
|
|
|
t = ns - tc->time_zero;
|
|
quot = t / tc->time_mult;
|
|
rem = t % tc->time_mult;
|
|
return (quot << tc->time_shift) +
|
|
(rem << tc->time_shift) / tc->time_mult;
|
|
}
|
|
|
|
u64 tsc_to_perf_time(u64 cyc, struct perf_tsc_conversion *tc)
|
|
{
|
|
u64 quot, rem;
|
|
|
|
if (tc->cap_user_time_short)
|
|
cyc = tc->time_cycles +
|
|
((cyc - tc->time_cycles) & tc->time_mask);
|
|
|
|
quot = cyc >> tc->time_shift;
|
|
rem = cyc & (((u64)1 << tc->time_shift) - 1);
|
|
return tc->time_zero + quot * tc->time_mult +
|
|
((rem * tc->time_mult) >> tc->time_shift);
|
|
}
|
|
|
|
int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc,
|
|
struct perf_tsc_conversion *tc)
|
|
{
|
|
u32 seq;
|
|
int i = 0;
|
|
|
|
while (1) {
|
|
seq = pc->lock;
|
|
rmb();
|
|
tc->time_mult = pc->time_mult;
|
|
tc->time_shift = pc->time_shift;
|
|
tc->time_zero = pc->time_zero;
|
|
tc->time_cycles = pc->time_cycles;
|
|
tc->time_mask = pc->time_mask;
|
|
tc->cap_user_time_zero = pc->cap_user_time_zero;
|
|
tc->cap_user_time_short = pc->cap_user_time_short;
|
|
rmb();
|
|
if (pc->lock == seq && !(seq & 1))
|
|
break;
|
|
if (++i > 10000) {
|
|
pr_debug("failed to get perf_event_mmap_page lock\n");
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
if (!tc->cap_user_time_zero)
|
|
return -EOPNOTSUPP;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int perf_event__synth_time_conv(const struct perf_event_mmap_page *pc,
|
|
struct perf_tool *tool,
|
|
perf_event__handler_t process,
|
|
struct machine *machine)
|
|
{
|
|
union perf_event event = {
|
|
.time_conv = {
|
|
.header = {
|
|
.type = PERF_RECORD_TIME_CONV,
|
|
.size = sizeof(struct perf_record_time_conv),
|
|
},
|
|
},
|
|
};
|
|
struct perf_tsc_conversion tc;
|
|
int err;
|
|
|
|
if (!pc)
|
|
return 0;
|
|
err = perf_read_tsc_conversion(pc, &tc);
|
|
if (err == -EOPNOTSUPP)
|
|
return 0;
|
|
if (err)
|
|
return err;
|
|
|
|
pr_debug2("Synthesizing TSC conversion information\n");
|
|
|
|
event.time_conv.time_mult = tc.time_mult;
|
|
event.time_conv.time_shift = tc.time_shift;
|
|
event.time_conv.time_zero = tc.time_zero;
|
|
event.time_conv.time_cycles = tc.time_cycles;
|
|
event.time_conv.time_mask = tc.time_mask;
|
|
event.time_conv.cap_user_time_zero = tc.cap_user_time_zero;
|
|
event.time_conv.cap_user_time_short = tc.cap_user_time_short;
|
|
|
|
return process(tool, &event, NULL, machine);
|
|
}
|
|
|
|
u64 __weak rdtsc(void)
|
|
{
|
|
return 0;
|
|
}
|