Accurate boot time measurement
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Cover letter [U-Boot] [PATCH 0/4] Accurate boot time measurement
Quoted 30 lines · Simon Glass
Quoted 6 lines · Mike Frysinger
Quoted 1 line · On Friday, May 13, 2011 16:51:59 Simon Glass wrote:
This defines the basics of a new boot time measurement feature. This
allows
Quoted 3 lines
logging of very accurate time measurements as the boot proceeds, by using an available microsecond counter.
Quoted 9 lines
Quoted 3 lines
To enable the feature, define
CONFIG_BOOTSTAGEin your board config file. Also available isCONFIG_BOOTSTAGE_REPORTwhich will cause a report to be printed just before handing off to the OS.this seems to overlap the existing
show_boot_progress()code. any chance we
can look at these being merged ?
-mikeHi Mike,
Yes I did look at this a few weeks ago. It would be a pretty invasive change. That code just uses a whole lot of numbers which presumably are approximately how far through the boot process we are. Bootstage is intended as a debugging tool for performance tune-up rather than a user display tool. I could imagine adding a table to bootstage with the progess number for each bootstage id, but then people are going to complain that the bootstage report is far to long and includes uninteresting things. I suppose I could fix that by including a flag as to whether to report each item or not...but it any case as you can see it is not a clear win.
Quoted 5 lines
If there is a strong appetite for that sort of patch I'm happy to do it.
Regards,
Simon
Couple of thoughts:
- Macro the definition of show_boot_progress() so it accepts a (const char *) argument if CONFIG_BOOTSTAGE is defined
- Change BOOTSTAGE_COUNT to CONFIG_MAX_BOOTSTAGE_RECORDS
- Any call to show_boot_progress() with a non-null second argument causes it to be logged in the next available bootstage record
- After the last bootstage record is filled, no further calls to show_boot_progress() cause logging to the bootstage records
- Instead of CONFIG_BOOTSTAGE_REPORT, create a command which dumps the contents of the bootstage records
No this is going to result in a big patch (every instance of show_boot_progress() will need to be touched to at least add NULL as the second parameter - Maintainers can add better text later ;)
Regards,
Graeme