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SubjectRe: [PATCH V6 13/15] perf intel-pt: Add support for text poke events
On Sun, Apr 05, 2020 at 11:13:25PM +0300, Adrian Hunter wrote:
> Select text poke events when available and the kernel is being traced.
> Process text poke events to invalidate entries in Intel PT's instruction
> cache.
>
> Example:
>
> The example requires kernel config:
> CONFIG_PROC_SYSCTL=y
> CONFIG_SCHED_DEBUG=y
> CONFIG_SCHEDSTATS=y
>
> Before:
>
> # perf record -o perf.data.before --kcore -a -e intel_pt//k -m,64M &
> # cat /proc/sys/kernel/sched_schedstats
> 0
> # echo 1 > /proc/sys/kernel/sched_schedstats
> # cat /proc/sys/kernel/sched_schedstats
> 1
> # echo 0 > /proc/sys/kernel/sched_schedstats
> # cat /proc/sys/kernel/sched_schedstats
> 0
> # kill %1
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 3.341 MB perf.data.before ]
> [1]+ Terminated perf record -o perf.data.before --kcore -a -e intel_pt//k -m,64M
> # perf script -i perf.data.before --itrace=e >/dev/null
> Warning:
> 474 instruction trace errors
>
> After:
>
> # perf record -o perf.data.after --kcore -a -e intel_pt//k -m,64M &
> # cat /proc/sys/kernel/sched_schedstats
> 0
> # echo 1 > /proc/sys/kernel/sched_schedstats
> # cat /proc/sys/kernel/sched_schedstats
> 1
> # echo 0 > /proc/sys/kernel/sched_schedstats
> # cat /proc/sys/kernel/sched_schedstats
> 0
> # kill %1
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 2.646 MB perf.data.after ]
> [1]+ Terminated perf record -o perf.data.after --kcore -a -e intel_pt//k -m,64M
> # perf script -i perf.data.after --itrace=e >/dev/null


I'm still seeing some, probably I'm missing some CONFIG, will check

# ./perf record -o perf.data.after --kcore -a -e intel_pt//k -m,64M &
[1] 5880
# cat /proc/sys/kernel/sched_schedstats
0
# echo 1 > /proc/sys/kernel/sched_schedstats
# cat /proc/sys/kernel/sched_schedstats
1
# echo 0 > /proc/sys/kernel/sched_schedstats
# kill %1
# [ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 6.181 MB perf.data.after ]
[1]+ Terminated ./perf record -o perf.data.after --kcore -a -e intel_pt//k -m,64M
# ./perf script --itrace=e -i perf.data.after > /dev/null
Warning:
18837 instruction trace errors

# ./perf script --itrace=e -i perf.data.after | head
instruction trace error type 1 time 9274.420582345 cpu 9 pid 845 tid 845 ip 0xffffffff814e6cf2 code 6: Trace doesn't match instruction
instruction trace error type 1 time 9274.422229726 cpu 39 pid 5880 tid 5880 ip 0xffffffffa030a320 code 6: Trace doesn't match instruction
instruction trace error type 1 time 9274.422231972 cpu 39 pid 5880 tid 5880 ip 0xffffffffa0315c1c code 6: Trace doesn't match instruction
instruction trace error type 1 time 9274.422236141 cpu 39 pid 5880 tid 5880 ip 0xffffffff81143263 code 6: Trace doesn't match instruction
instruction trace error type 1 time 9274.422237424 cpu 39 pid 5880 tid 5880 ip 0xffffffff8115c388 code 6: Trace doesn't match instruction
instruction trace error type 1 time 9274.422239028 cpu 39 pid 5880 tid 5880 ip 0xffffffff811428c9 code 6: Trace doesn't match instruction
instruction trace error type 1 time 9274.422239028 cpu 39 pid 5880 tid 5880 ip 0xffffffffa13279fb code 5: Failed to get instruction
instruction trace error type 1 time 9274.422242556 cpu 39 pid 5880 tid 5880 ip 0xffffffff814e9c73 code 6: Trace doesn't match instruction
instruction trace error type 1 time 9274.422258915 cpu 39 pid 5880 tid 5880 ip 0xffffffff810d7da2 code 6: Trace doesn't match instruction
instruction trace error type 1 time 9274.422258915 cpu 39 pid 5880 tid 5880 ip 0xffffffffa030a0b2 code 6: Trace doesn't match instruction

jirka

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