diff options
Diffstat (limited to 'en/devices/tech/perf/boot-times.html')
| -rw-r--r-- | en/devices/tech/perf/boot-times.html | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/en/devices/tech/perf/boot-times.html b/en/devices/tech/perf/boot-times.html index a7588301..fb6ad441 100644 --- a/en/devices/tech/perf/boot-times.html +++ b/en/devices/tech/perf/boot-times.html @@ -255,17 +255,27 @@ us uncover many meaningful bugs in some Android device drivers). Many processes launch during boot, but only components in critical path (bootloader > kernel > init > file system mount > zygote > system server) directly affect boot time. Profile <strong>initcall</strong> during kernel -booting to identify peripheral/components that are not critical to the -start init process, then delay those peripherals/components until later -in the boot process. +booting to identify peripheral/components that are slow and not critical +to start init process, then delay those peripherals/components until later +in the boot process by moving into loadable kernel modules. Moving to +asynchronous device/driver probe can also help to parallel slow components +in kernel > init critical path. </p> <pre class="prettyprint"> BoardConfig-common.mk: BOARD_KERNEL_CMDLINE += initcall_debug ignore_loglevel + +driver: + .probe_type = PROBE_PREFER_ASYNCHRONOUS, </pre> +<p class="note"> +<strong>Note:</strong> Driver dependencies must be resolved carefully by adding +<code>EPROBEDEFER</code> support. +</p> + <h2 id="optimizing-i-o-efficiency">Optimizing I/O efficiency</h2> <p> @@ -422,6 +432,12 @@ early stage init should be deferred to boot completed.</li></ul> </li> </ul> +<p class="note"> +<strong>Note:</strong> Property service is part of init process, so calling +<code>setproperty</code> during boot can lead a long delay if init is busy in +builtin commands. +</p> + <h3 id="using-scheduler-tuning">Using scheduler tuning</h3> <p> |