Messages in this thread | | | Date | Tue, 23 Oct 2012 08:19:51 +0100 | From | Lee Jones <> | Subject | Re: [PATCH] Boottime: A tool for automatic measurement of kernel/bootloader boot time |
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I have a few answers for you.
> >>>>>>root@ME:/ cat /sys/kernel/debug/boottime/bootgraph > >>>>>>[ 0.185254] calling splash+0x0/0x0 > >>>>>>[ 2.984335] initcall splash+0x0/0x0 returned 0 after 2799 msecs. > >>>>>>[ 2.984335] calling autoboot_delay+0x0/0x0 > >>>>>>[ 4.089513] initcall autoboot_delay+0x0/0x0 returned 0 after 1105 msecs. > >>>>>>[ 4.089513] calling load_kernel+0x0/0x0 > >>>>>>[ 4.239174] initcall load_kernel+0x0/0x0 returned 0 after 149 msecs. > >>>>>>[ 4.239174] calling boot_kernel+0x0/0x0 > >>>>>>[ 4.276260] initcall boot_kernel+0x0/0x0 returned 0 after 37 msecs. > >>>>>>[ 4.276260] calling uncompress_ll_init+0x0/0x0 > >>>>>>[ 4.276260] initcall uncompress_ll_init+0x0/0x0 returned 0 after 0 msecs. > >>>>>>[ 4.276260] Freeing init memory: 0K
> OK So has this been validated and tested on any other IC then a ST part?
No, it has not. As I believe I mentioned before, this is a tool written for and used by ST-Ericsson. Extending it to use on other platforms sounds like a great idea, but won't be done by ST-Ericsson due to a lack of hardware and software assets.
> This boottime_activate patch seems to be only for the dbx500. If > this is supposed to be a generic solution I would expect > a generic patch for ARM to enable boot time activation.
Apparently a generic boottime extention would be fairly trivial with the use of ktime_get().
> Have you profiled how much time the boot time logging has added to > the over all boot?
This has not been completed, but the original author suspects it would be <100ms.
> Also the boottime commit message should explain a little more what > it is measuring. > i.e. This patch enables logging the boot time from point x to point > y for the kernel only. This does not include init. > What about adding the boot time from the init sequence to init complete?
This sounds like a good idea, but again won't be extended upon by us.
It appears that this driver is interesting and possibly very useful for quite a lot of people out there. This patch should therefore be seen as the foundations for other to then extend in the ways alluded to above and ported to work on other more generic platforms. I think these should be extra patches on top of the one submitted here.
From a personal perspective, I am happy to change a few bits and pieces, but I don't have the time to satisfy all of the suggestions made, or adapt the driver in any substantial manor.
-- Lee Jones Linaro ST-Ericsson Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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