kernel/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c, branch linux-4.15.y

perf intel-pt: Do not use TSC packets for calculating CPU cycles to TSC

2017-06-30T14:50:55Z

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 Cc: Andi Kleen Link: http://lkml.kernel.org/r/1495786658-18063-37-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Add decoder support for CBR events

2017-06-21T14:35:51Z

Add decoder support for informing the tools of changes to the core-to-bus ratio (CBR). Signed-off-by: Adrian Hunter Cc: Andi Kleen Link: http://lkml.kernel.org/r/1495786658-18063-16-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Add reserved byte to CBR packet payload

2017-06-21T14:35:50Z

Future proof CBR packet decoding by passing through also the undefined 'reserved' byte in the packet payload. Signed-off-by: Adrian Hunter Cc: Andi Kleen Link: http://lkml.kernel.org/r/1495786658-18063-15-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Add decoder support for ptwrite and power event packets

2017-06-21T14:35:50Z

Add decoder support for PTWRITE, MWAIT, PWRE, PWRX and EXSTOP packets. This patch only affects the decoder, so the tools still do not select or consume the new information. That is added in subsequent patches. Signed-off-by: Adrian Hunter Cc: Andi Kleen Link: http://lkml.kernel.org/r/1495786658-18063-14-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Allow decoding with branch tracing disabled

2017-06-21T14:35:48Z

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 Cc: Andi Kleen Link: http://lkml.kernel.org/r/1495786658-18063-11-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Add missing __fallthrough

2017-06-21T14:35:47Z

perf tools uses __fallthrough. Add missing __fallthrough to a switch statement. Signed-off-by: Adrian Hunter Cc: Andi Kleen Link: http://lkml.kernel.org/r/1495786658-18063-10-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Clear FUP flag on error

2017-06-21T14:35:47Z

Sometimes a FUP packet is associated with a TSX transaction and a flag is set to indicate that. Ensure that flag is cleared on any error condition because at that point the decoder can no longer assume it is correct. Signed-off-by: Adrian Hunter Cc: Andi Kleen Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1495786658-18063-9-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Use FUP always when scanning for an IP

2017-06-21T14:35:46Z

The decoder will try to use branch packets to find an IP to start decoding or to recover from errors. Currently the FUP packet is used only in the case of an overflow, however there is no reason for that to be a special case. So just use FUP always when scanning for an IP. Signed-off-by: Adrian Hunter Cc: Andi Kleen Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1495786658-18063-8-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Ensure never to set 'last_ip' when packet 'count' is zero

2017-06-21T14:35:46Z

Intel PT uses IP compression based on the last IP. For decoding purposes, 'last IP' is not updated when a branch target has been suppressed, which is indicated by IPBytes == 0. IPBytes is stored in the packet 'count', so ensure never to set 'last_ip' when packet 'count' is zero. Signed-off-by: Adrian Hunter Cc: Andi Kleen Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1495786658-18063-7-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Fix last_ip usage

2017-06-21T14:35:45Z

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 Cc: Andi Kleen 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