Re: [PATCH v3 2/6] perf arm-spe: Save clock parameters from TIME_CONV event
From: Leo Yan <hidden>
Date: 2021-04-12 00:17:37
Also in:
lkml
On Sat, Apr 10, 2021 at 01:00:42PM +0800, Leo Yan wrote:
During the recording phase, "perf record" tool synthesizes event PERF_RECORD_TIME_CONV for the hardware clock parameters and saves the event into the data file. Afterwards, when processing the data file, the event TIME_CONV will be processed at the very early time and is stored into session context. This patch extracts these parameters from the session context and saves into the structure "spe->tc" with the type perf_tsc_conversion, so that the parameters are ready for conversion between clock counter and time stamp. Signed-off-by: Leo Yan <redacted>
[...]
quoted hunk ↗ jump to hunk
--- tools/perf/util/arm-spe.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c index 2539d4baec44..b48816d5c0b4 100644 --- a/tools/perf/util/arm-spe.c +++ b/tools/perf/util/arm-spe.c@@ -26,6 +26,7 @@ #include "symbol.h" #include "thread.h" #include "thread-stack.h" +#include "tsc.h" #include "tool.h" #include "util/synthetic-events.h"@@ -45,6 +46,8 @@ struct arm_spe { struct machine *machine; u32 pmu_type; + struct perf_tsc_conversion tc; + u8 timeless_decoding; u8 data_queued;@@ -1027,6 +1030,22 @@ int arm_spe_process_auxtrace_info(union perf_event *event, spe->pmu_type = auxtrace_info->priv[ARM_SPE_PMU_TYPE]; spe->timeless_decoding = arm_spe__is_timeless_decoding(spe); + + /* + * The synthesized event PERF_RECORD_TIME_CONV has been handled + * ahead and the parameters for hardware clock are stored in + * the session context. Passes these parameters to the structure + * perf_tsc_conversion in "spe->tc", which is used for later + * conversion between clock counter and timestamp. + */ + spe->tc.time_shift = session->time_conv.time_shift; + spe->tc.time_mult = session->time_conv.time_mult; + spe->tc.time_zero = session->time_conv.time_zero; + spe->tc.time_cycles = session->time_conv.time_cycles; + spe->tc.time_mask = session->time_conv.time_mask; + spe->tc.cap_user_time_zero = session->time_conv.cap_user_time_zero; + spe->tc.cap_user_time_short = session->time_conv.cap_user_time_short;
As Adrain suggested, this patch also should check the size of event PERF_RECORD_TIME_CONV for backwards-compability. I will send a new patch set for this. Thanks, Leo
spe->auxtrace.process_event = arm_spe_process_event; spe->auxtrace.process_auxtrace_event = arm_spe_process_auxtrace_event; spe->auxtrace.flush_events = arm_spe_flush; -- 2.25.1
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