System calls
On Linux and Android (userdebug builds only) Perfetto can keep track of system calls.
Right now only the syscall number is recorded in the trace, the arguments are not stored to limit the trace size overhead.
At import time, the Trace Processor uses an internal syscall mapping table,
currently supporting x86, x86_64, ArmEabi, aarch32 and aarch64. These tables are
generated through the
extract_linux_syscall_tables
script.
UI
At the UI level system calls are shown inlined with the per-thread slice tracks:
SQL
At the SQL level, syscalls are no different than any other userspace slice event. They get interleaved in the per-thread slice stack and can be easily filtered by looking for the 'sys_' prefix:
select ts, dur, t.name as thread, s.name, depth from slices as s
left join thread_track as tt on s.track_id = tt.id
left join thread as t on tt.utid = t.utid
where s.name like 'sys_%'
ts | dur | thread | name |
---|---|---|---|
856325324372751 | 439867648 | s.nexuslauncher | sys_epoll_pwait |
856325324376970 | 990 | FpsThrottlerThr | sys_recvfrom |
856325324378376 | 2657 | surfaceflinger | sys_ioctl |
856325324419574 | 1250 | android.anim.lf | sys_recvfrom |
856325324428168 | 27344 | android.anim.lf | sys_ioctl |
856325324451345 | 573 | FpsThrottlerThr | sys_getuid |
TraceConfig
data_sources: {
config {
name: "linux.ftrace"
ftrace_config {
ftrace_events: "raw_syscalls/sys_enter"
ftrace_events: "raw_syscalls/sys_exit"
}
}
}