There are some edge cases around estimated timestamps that can result
in them going backwards.
One is that after a discontinuity, the last used timestamp is set to 0.
The duration of the next range is then subtracted which could result in
an earlier timestamp than the last instruction. Fix this by not
resetting the last timestamp used on a discontinuity, and make sure that
new estimated timestamps are clamped to be later than that.
Another case is that estimated timestamps could compound over time to
end up being more than the next real timestamp in the trace. Fix this by
clamping the estimates in cs_etm_decoder__do_soft_timestamp() to be no
later than it.
cs_etm_decoder__do_soft_timestamp() also updated next_cs_timestamp,
which meant that the next real timestamp was lost and not stored
anywhere. Fix that by only updating cs_timestamp for estimates and keep
next_cs_timestamp untouched.
Finally, use next_cs_timestamp to signify if a timestamp has been
received previously. Because cs_timestamp has the first range
subtracted, it could technically go to 0 which would break the logic.
Testing
=======
It can be verified that timestamps don't go backwards when tracing on a
single core with the following commands. Across multiple cores it's
expected that timestamps are interleaved:
$ perf record -e cs_etm/@tmc_etr0/k -C 4 taskset -c 4 sleep 1
$ perf script --itrace=i1ns --ns -Fcomm,tid,pid,time,cpu,event,ip,sym,addr,symoff,flags,callindent > itrace
$ sed 's/://g' itrace | awk -F ' ' ' { print $4 } ' | awk '{ if ($1 < prev) { print "line:" NR " " $0 } {prev=$1}}'
Reported-by: Tanmay Jagdale <tanmay@marvell.com>
Signed-off-by: James Clark <james.clark@arm.com>
Acked-by: Suzuki Poulouse <suzuki.poulose@arm.com>
Tested-by: Tanmay Jagdale <tanmay@marvell.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Bharat Bhushan <bbhushan2@marvell.com>
Cc: George Cherian <gcherian@marvell.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Linu Cherian <lcherian@marvell.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Cc: Will Deacon <will@kernel.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230120143702.4035046-9-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
If virtual timestamps are detected, set sample time field accordingly,
otherwise warn the user that the samples will not include accurate
time data.
| Test notes (FEAT_TRF platform)
|
| $ ./perf record -e cs_etm//u -a -- sleep 4
| $ ./perf script --fields +time
| perf 422 [000] 163.375100: 1 branches:uH: 0 [unknown] ([unknown])
| perf 422 [000] 163.375100: 1 branches:uH: ffffb8009544 ioctl+0x14 (/lib/aarch64-linux-gnu/libc-2.27.so)
| perf 422 [000] 163.375100: 1 branches:uH: aaaaab6bebf4 perf_evsel__run_ioctl+0x90 (/home/german/linux/tools/perf/perf)
| [...]
| perf 422 [000] 167.393100: 1 branches:uH: aaaaab6bda00 __xyarray__entry+0x74 (/home/german/linux/tools/perf/perf)
| perf 422 [000] 167.393099: 1 branches:uH: aaaaab6bda0c __xyarray__entry+0x80 (/home/german/linux/tools/perf/perf)
| perf 422 [000] 167.393099: 1 branches:uH: ffffb8009538 ioctl+0x8 (/lib/aarch64-linux-gnu/libc-2.27.so)
|
| The time from the first sample to the last sample is 4 seconds
Now that times are converted to nanoseconds, also try to estimate the
timestamps more accurately be dividing by some fixed value for
instructions per ns. This prevents long ranges from being estimated
too far in the past than would be realistic.
Signed-off-by: German Gomez <german.gomez@arm.com>
Acked-by: Suzuki Poulouse <suzuki.poulose@arm.com>
Tested-by: Tanmay Jagdale <tanmay@marvell.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Bharat Bhushan <bbhushan2@marvell.com>
Cc: George Cherian <gcherian@marvell.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Linu Cherian <lcherian@marvell.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Cc: Will Deacon <will@kernel.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230120143702.4035046-8-james.clark@arm.com
Signed-off-by: James Clark <james.clark@arm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The following error was thrown when compiling `tools/perf` using OpenCSD
v0.11.1. This patch fixes said error.
CC util/intel-pt-decoder/intel-pt-log.o
CC util/cs-etm-decoder/cs-etm-decoder.o
util/cs-etm-decoder/cs-etm-decoder.c: In function
‘cs_etm_decoder__buffer_range’:
util/cs-etm-decoder/cs-etm-decoder.c:370:2: error: enumeration value
‘OCSD_INSTR_WFI_WFE’ not handled in switch [-Werror=switch-enum]
switch (elem->last_i_type) {
^~~~~~
CC util/intel-pt-decoder/intel-pt-decoder.o
cc1: all warnings being treated as errors
Because `OCSD_INSTR_WFI_WFE` case was added only in v0.11.0, the minimum
required OpenCSD library version for this patch is no longer v0.10.0.
Signed-off-by: Solomon Tan <solomonbobstoner@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: Suzuki K Poulouse <suzuki.poulose@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20190322052255.GA4809@w-OptiPlex-7050
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
If packet processing wants to know the packet is bound with which ETM
version, it needs to access metadata to decide that based on metadata
magic number; but we cannot simply to use CPU logic ID number as index
to access metadata sequential array, especially when system have
hotplugged off CPUs, the metadata array are only allocated for online
CPUs but not offline CPUs, so the CPU logic number doesn't match with
its index in the array.
This patch is to change tuple from traceID-CPU# to traceID-metadata,
thus it can use the tuple to retrieve metadata pointer according to
traceID.
For safe accessing metadata fields, this patch provides helper function
cs_etm__get_cpu() which is used to return CPU number according to
traceID; cs_etm_decoder__buffer_packet() is the first consumer for this
helper function.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: Suzuki K Poulouse <suzuki.poulose@arm.com>
Cc: coresight ml <coresight@lists.linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20190129122842.32041-6-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Decoder provides last instruction related information, these information
can be used for trace analysis; specifically we can get to know what
kind of branch instruction has been executed, mainly the information are
contained in three element fields:
last_i_type: this is significant type for waypoint calculation, it
indicates the last instruction is one of immediate branch instruction,
indirect branch instruction, instruction barrier (ISB), or data
barrier (DSB/DMB).
last_i_subtype: this is used for instruction sub type, it can be
branch with link, ARMv8 return instruction, ARMv8 eret instruction
(return from exception), or ARMv7 instruction which could imply
return (e.g. MOV PC, LR; POP { ,PC}).
last_instr_cond: it indicates if the last instruction was conditional.
But these three fields are not saved into cs_etm_packet struct, thus
cs-etm layer don't know related information and cannot generate sample
flags for branch instructions.
This patch add corresponding three new fields in cs_etm_packet struct
and save related value into the packet structure, it is preparation for
supporting sample flags.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: Suzuki K Poulouse <suzuki.poulose@arm.com>
Cc: coresight ml <coresight@lists.linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20190129122842.32041-2-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The exception packet appears as one element with 'elem_type' ==
OCSD_GEN_TRC_ELEM_EXCEPTION or OCSD_GEN_TRC_ELEM_EXCEPTION_RET, which is
present for exception entry and exit respectively. The decoder sets the
packet fields 'packet->exc' and 'packet->exc_ret' to indicate the
exception packets; but exception packets don't have a dedicated sample
type and shares the same sample type CS_ETM_RANGE with normal
instruction packets.
As a result, the exception packets are taken as normal instruction
packets and this introduces confusion in mixing different packet types.
Furthermore, these instruction range packets will be processed for
branch samples only when 'packet->last_instr_taken_branch' is true,
otherwise they will be omitted, this can introduce a mess for exception
and exception returning due to not having the complete address range
info for context switching.
To process exception packets properly, this patch introduces two new
sample types: CS_ETM_EXCEPTION and CS_ETM_EXCEPTION_RET; these two types
of packets will be handled by cs_etm__exception(). The function
cs_etm__exception() forces setting the previous CS_ETM_RANGE packet flag
'prev_packet->last_instr_taken_branch' to true, this matches well with
the program flow when the exception is trapped from user space to kernel
space, no matter if the most recent flow has branch taken or not; this
is also safe for returning to user space after exception handling.
After exception packets have their own sample type, the packet fields
'packet->exc' and 'packet->exc_ret' aren't needed anymore, so remove
them.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: coresight ml <coresight@lists.linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1544513908-16805-9-git-send-email-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The CoreSight tracer driver might insert barrier packets between
different buffers, thus the decoder can spot the boundaries based on the
barrier packet; it is possible for the decoder to hit a barrier packet
and emit a NO_SYNC element, then the decoder will find a periodic
synchronisation point inside that next trace block that starts the trace
again but does not have the TRACE_ON element as indicator - usually
because this trace block has wrapped the buffer so we have lost the
original point when the trace was enabled.
In the first case it causes the insertion of a OCSD_GEN_TRC_ELEM_NO_SYNC
in the middle of the tracing stream, but as we were not handling the
NO_SYNC element properly this ends up making users miss the
discontinuity indications.
Though OCSD_GEN_TRC_ELEM_NO_SYNC is different from CS_ETM_TRACE_ON when
output from the decoder, both indicate that the trace data is
discontinuous; this patch treats OCSD_GEN_TRC_ELEM_NO_SYNC as a trace
discontinuity and generates a CS_ETM_DISCONTINUITY packet for it, so
cs-etm can handle the discontinuity for this case, finally it saves the
last trace data for the previous trace block and restart samples for the
new block.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: coresight ml <coresight@lists.linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1544513908-16805-7-git-send-email-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
TRACE_ON element is used at the beginning of trace, it also can be
appeared in the middle of trace data to indicate discontinuity; for
example, it's possible to see multiple TRACE_ON elements in the trace
stream if the trace is being limited by address range filtering.
Furthermore, except TRACE_ON element is for discontinuity, NO_SYNC and
EO_TRACE also can be used to indicate discontinuity, though they are
used for different scenarios for which the trace is interrupted.
This patch renames sample type CS_ETM_TRACE_ON to CS_ETM_DISCONTINUITY,
firstly the new name describes more closely the purpose of the packet;
secondly this is a preparation for other output elements which also
cause the trace discontinuity thus they can share the same one packet
type.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1544513908-16805-6-git-send-email-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Added user space perf functionality to translate CoreSight traces into
instruction events with branch stack.
To invoke the new functionality, use the perf inject tool with
--itrace=il. For example, to translate the ETM trace from perf.data into
last branch records in a new inj.data file:
$ perf inject --itrace=i100000il128 -i perf.data -o perf.data.new
The 'i' parameter to itrace generates periodic instruction events. The
period between instruction events can be specified as a number of
instructions suffixed by i (default 100000).
The parameter to 'l' specifies the number of entries in the branch stack
attached to instruction events.
The 'b' parameter to itrace generates events on taken branches.
This patch also fixes the contents of the branch events used in perf
report - previously branch events were generated for each contiguous
range of instructions executed. These are fixed to generate branch
events between the last address of a range ending in an executed branch
instruction and the start address of the next range.
Based on patches by Sebastian Pop <s.pop@samsung.com> with additional fixes
and support for specifying the instruction period.
Originally-by: Sebastian Pop <s.pop@samsung.com>
Signed-off-by: Robert Walker <robert.walker@arm.com>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1518607481-4059-2-git-send-email-robert.walker@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
