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android – Failed to use systrace in Jelly Bean

Posted by: admin May 14, 2020 Leave a comment

Questions:

I’ve tried to use new systrace from jelly bean release, but with no luck.

I enabled graphics and views traces in development settings like on I/O session, and tried to call systrace, and all i get is this.

$ ./systrace.py               
error opening /sys/kernel/debug/tracing/options/overwrite: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/sched/sched_switch/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/sched/sched_wakeup/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/power/cpu_frequency/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/power/cpu_idle/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/buffer_size_kb: No such file or directory (2)
error opening /sys/kernel/debug/tracing/trace_clock: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/workqueue/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/ext4/ext4_sync_file_enter/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/ext4/ext4_sync_file_exit/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/block/block_rq_issue/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/block/block_rq_complete/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/tracing_on: No such file or directory (2)
error: unable to start trace
error opening /sys/kernel/debug/tracing/tracing_on: No such file or directory (2)
error opening /sys/kernel/debug/tracing/options/overwrite: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/sched/sched_switch/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/sched/sched_wakeup/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/power/cpu_frequency/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/trace_clock: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/workqueue/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/ext4/ext4_sync_file_enter/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/ext4/ext4_sync_file_exit/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/block/block_rq_issue/enable: No such file or directory (2)
error opening /sys/kernel/debug/tracing/events/block/block_rq_complete/enable: No such file or directory (2)
unable to start tracing
error opening /sys/kernel/debug/tracing/buffer_size_kb: No such file or directory (2)
An error occured while capturing the trace.  Output file was not written.

I’ve tried emulator and custom firmware on my Desire Hd (ace). Any thoughts?

How to&Answers:

try the following commands:

adb root (not sure if this is necessary),
adb shell mount -t debugfs nodev /sys/kernel/debug

Under these commands the script should run correctly, although for me the html file only contains rows for each CPU, and not the individual components such as surface flinger, which was visible in the google IO talks video.