linux/tools
Adrian Hunter c954eb72b3 perf intel-pt: Fix sample instruction bytes
The decoder reports the current instruction if it was decoded. In some
cases the current instruction is not decoded, in which case the instruction
bytes length must be set to zero. Ensure that is always done.

Note perf script can anyway get the instruction bytes for any samples where
they are not present.

Also note, that there is a redundant "ptq->insn_len = 0" statement which is
not removed until a subsequent patch in order to make this patch apply
cleanly to stable branches.

Example:

A machne that supports TSX is required. It will have flag "rtm". Kernel
parameter tsx=on may be required.

 # for w in `cat /proc/cpuinfo | grep -m1 flags `;do echo $w | grep rtm ; done
 rtm

Test program:

 #include <stdio.h>
 #include <immintrin.h>

 int main()
 {
        int x = 0;

        if (_xbegin() == _XBEGIN_STARTED) {
                x = 1;
                _xabort(1);
        } else {
                printf("x = %d\n", x);
        }
        return 0;
 }

Compile with -mrtm i.e.

 gcc -Wall -Wextra -mrtm xabort.c -o xabort

Record:

 perf record -e intel_pt/cyc/u --filter 'filter main @ ./xabort' ./xabort

Before:

 # perf script --itrace=xe -F+flags,+insn,-period --xed --ns
          xabort  1478 [007] 92161.431348581:   transactions:   x                              400b81 main+0x14 (/root/xabort)          mov $0xffffffff, %eax
          xabort  1478 [007] 92161.431348624:   transactions:   tx abrt                        400b93 main+0x26 (/root/xabort)          mov $0xffffffff, %eax

After:

 # perf script --itrace=xe -F+flags,+insn,-period --xed --ns
          xabort  1478 [007] 92161.431348581:   transactions:   x                              400b81 main+0x14 (/root/xabort)          xbegin 0x6
          xabort  1478 [007] 92161.431348624:   transactions:   tx abrt                        400b93 main+0x26 (/root/xabort)          xabort $0x1

Fixes: faaa87680b ("perf intel-pt/bts: Report instruction bytes and length in sample")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/20210519074515.9262-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2021-05-19 10:33:43 -03:00
..
accounting
arch tools arch kvm: Sync kvm headers with the kernel sources 2021-05-17 20:39:18 -03:00
bootconfig tools/bootconfig: Add tracing_on support to helper scripts 2021-01-14 10:32:20 -05:00
bpf bpftool: Dump more info about DATASEC members 2021-04-23 14:05:26 -07:00
build perf tools changes for v5.13: 1st batch 2021-05-01 12:22:38 -07:00
cgroup tools/cgroup/slabinfo.py: updated to work on current kernel 2021-04-23 14:42:40 -07:00
debugging tools: Fix a typo in kernel-chktaint 2021-04-08 11:41:22 -06:00
edid
firewire
firmware
gpio tools: gpio-utils: fix various kernel-doc warnings 2021-03-26 14:56:19 +01:00
hv
iio iio: event_monitor: Enable events before monitoring 2021-03-25 19:13:52 +00:00
include tools headers UAPI: Sync perf_event.h with the kernel sources 2021-05-10 09:01:01 -03:00
io_uring
kvm/kvm_stat tools/kvm_stat: Fix documentation typo 2021-05-07 06:06:22 -04:00
laptop
leds
lib Networking fixes for 5.13-rc1, including fixes from bpf, can 2021-05-08 08:31:46 -07:00
memory-model doc: update rcu_dereference.rst reference 2021-04-06 14:45:04 +02:00
objtool objtool/x86: Fix elf_add_alternative() endianness 2021-05-12 21:17:01 +02:00
pci
pcmcia
perf perf intel-pt: Fix sample instruction bytes 2021-05-19 10:33:43 -03:00
power Merge branch 'turbostat' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2021-05-05 12:24:29 -07:00
scripts tools: disable -Wno-type-limits 2021-05-06 19:24:11 -07:00
spi spi: tools: make a symbolic link to the header file spi.h 2021-04-22 16:30:39 +01:00
testing libnvdimm fixes for 5.13-rc2 2021-05-15 08:32:51 -07:00
thermal/tmon tools: do not include scripts/Kbuild.include 2021-04-25 05:26:13 +09:00
time
tracing tools/latency-collector: Remove unneeded semicolon 2021-03-18 12:58:26 -04:00
usb treewide: remove editor modelines and cruft 2021-05-07 00:26:34 -07:00
virtio
vm
wmi
Makefile tracing/tools: Add the latency-collector to tools directory 2021-02-12 11:52:59 -05:00