timestamp_insn_cnt is used to estimate the timestamp based on the number of
instructions since the last known timestamp.
If the estimate is not accurate enough decoding might not be correctly
synchronized with side-band events causing more trace errors.
However there are always timestamps following an overflow, so the
estimate is not needed and can indeed result in more errors.
Suppress the estimate by setting timestamp_insn_cnt to zero.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1520431349-30689-5-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
CBR (core-to-bus ratio) packets provide an indication of CPU frequency. A
more accurate measure can be made by counting the cycles (given by CYC
packets) in between other timing packets (either MTC or TSC). Using TSC
packets has at least 2 issues: 1) timing might have stopped (e.g. mwait) or
2) TSC packets within PSB+ might slip past CYC packets. For now, simply do
not use TSC packets for calculating CPU cycles to TSC. That leaves the case
where 2 MTC packets are used, otherwise falling back to the CBR value.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1495786658-18063-37-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The kernel now supports the disabling of branch tracing, however the
decoder assumes branch tracing is always enabled. Pass through a parameter
to indicate whether branch tracing is enabled and use it to avoid cases
when the decoder is expecting branch packets. There are 2 such cases.
First, FUP packets which can bind to an IP even when there is no branch
tracing. Secondly, the decoder will try to use branch packets to find an IP
to start decoding or to recover from errors.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1495786658-18063-11-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Intel PT uses IP compression based on the last IP. For decoding
purposes, 'last IP' is considered to be reset to zero whenever there is
a synchronization packet (PSB). The decoder wasn't doing that, and was
treating the zero value to mean that there was no last IP, whereas
compression can be done against the zero value. Fix by setting last_ip
to zero when a PSB is received and keep track of have_last_ip.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1495786658-18063-6-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To address new warnings emmited by gcc 7, e.g.::
CC /tmp/build/perf/util/intel-pt-decoder/intel-pt-pkt-decoder.o
CC /tmp/build/perf/tests/parse-events.o
util/intel-pt-decoder/intel-pt-pkt-decoder.c: In function 'intel_pt_pkt_desc':
util/intel-pt-decoder/intel-pt-pkt-decoder.c:499:6: error: this statement may fall through [-Werror=implicit-fallthrough=]
if (!(packet->count))
^
util/intel-pt-decoder/intel-pt-pkt-decoder.c:501:2: note: here
case INTEL_PT_CYC:
^~~~
CC /tmp/build/perf/util/intel-pt-decoder/intel-pt-decoder.o
cc1: all warnings being treated as errors
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-mf0hw789pu9x855us5l32c83@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Change Intel PT and BTS to pass up the length and the instruction
bytes of the decoded or sampled instruction in the perf sample.
The decoder already knows this information, we just need to pass it
up. Since it is only a couple of movs it is not very expensive.
Handle instruction cache too. Make sure ilen is always initialized.
Used in the next patch.
[Adrian: re-base on top (and adjust for) instruction buffer size tidy-up]
[Adrian: add BTS support and adjust commit message accordingly]
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Link: http://lkml.kernel.org/r/1475847747-30994-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The MTC packet provides a 8-bit slice of CTC which is related to TSC by
the TMA packet, however the TMA packet only provides the lower 16 bits
of CTC. If mtc_shift > 8 then some of the MTC bits are not in the CTC
provided by the TMA packet. Fix-up the last_mtc calculated from the TMA
packet by copying the missing bits from the current MTC assuming the
least difference between the two, and that the current MTC comes after
last_mtc.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org # v4.3+
Link: http://lkml.kernel.org/r/1475062896-22274-2-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When address filters are used, the decoder must detect the end of a
filter region (or a branch into a tracestop region) by matching Packet
Generation Disabled (TIP.PGD) packets against the object code using the
IP given in the packet. However, due to errata SKL014 "Intel PT TIP.PGD
May Not Have Target IP Payload", that IP may not be present.
Enable the decoder to handle that by adding a new callback function
'pgd_ip()' which indicates whether the IP is not traced, in which case
that is the point where the trace was disabled.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: http://lkml.kernel.org/r/1474641528-18776-16-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
