On Thu, Jul 20, 2017 at 11:24:22AM -0700, Mark Salyzyn wrote: > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 98fe715522e8..0d63c3fb4e24 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -30,6 +30,58 @@ config CONSOLE_LOGLEVEL_DEFAULT > usage in the kernel. That is controlled by the > MESSAGE_LOGLEVEL_DEFAULT > option. > > +# set if time is being printed in pr_info_show_time() > +config PR_INFO_SHOW_TIME > + bool > + > +choice > + prompt "pr_info_show_time() alternate time message prefix" > + help > + Activate alternate time prefix in pr_info_show_time > + > + The primary use of the instrumentation is to aid field > + analysis of Battery and Power usage. The instrumentation > + may also help triage and synchronize kernel logs and user > + space activity logs at key displacements. > + config PR_INFO_SHOW_TIME_MONOTONIC > + bool "monotonic" > + help > + Deactivate alternate time prefix in pr_info_show_time. > + Doing so because monotonic time is part of the normal > + printk time logging. > + > + Print only the supplied message in pr_info_show_time, > + indistinguishable from pr_info. > + config PR_INFO_SHOW_TIME_REALTIME > + bool "realtime" > + select PR_INFO_SHOW_TIME > + help > + Activate alternate time prefix in pr_info_show_time > + > + The primary use of the instrumentation is to aid field > + analysis of Battery and Power usage. The instrumentation > + may also help triage and synchronize kernel logs and user > + space activity logs at key displacements. For instance > + CLOCK_MONOTONIC stops while suspended, while CLOCK_REALTIME > + continues, and the timestamps help re-orient post-analysis. > + > + Prefix realtime [<epoch>.<ns>U] timestamp in pr_info_show_time > + config PR_INFO_SHOW_TIME_BOOTTIME > + bool "boottime" > + select PR_INFO_SHOW_TIME > + help > + Activate alternate time prefix in pr_info_show_time > + > + The primary use of the instrumentation is to aid field > + analysis of Battery and Power usage. The instrumentation > + may also help triage and synchronize kernel logs and user > + space activity logs at key displacements. For instance > + CLOCK_MONOTONIC stops while suspended, while CLOCK_BOOTTIME > + continues, and the timestamps help re-orient post-analysis. > + > + Prefix boottime [<epoch>.<ns>B] timestamp in pr_info_show_time > +endchoice
There is no depends magic anywhere here, so none of this actually has complex dependencies, this is just boot time preference setup, and for that I think a boot param and sysctl value could easily not only enable the same but *also* enable run time ability to swap between these. Even for the branch performance consideration can't jump labels be used to address that if there is a concern for that? I think that would also make the code easier to read and remove all this kconfig extra stuff. Then its just a run time thing. Also, should there be no checks for time being available and ready before this is used? Luis
