Re: [PATCH V6 13/15] perf intel-pt: Add support for text poke events

[Adrian Hunter]

On 21/04/20 4:06 pm, Jiri Olsa wrote:
> On Tue, Apr 21, 2020 at 04:02:32PM +0300, Adrian Hunter wrote:
>> On 21/04/20 3:50 pm, Jiri Olsa wrote:
>>> 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
>>
>> I don't think it can be CONFIG.  Can you share the branch you are using?
>> Then I can test it.
>>
> 
> I built the one you mentioned in cover email:
>   git://git.infradead.org/users/ahunter/linux-perf.git text_poke

The tools and the kernel?

Does it successfully decode anything? e.g.
./perf script --itrace=be -i perf.data.after | head