On 02/08/11 04:21, Ingo Molnar wrote: < snip > > Also, i've Cc:-ed Linus, to check whether the idea to make power management a > permanent, core portion of Linux has any obvious downsides we missed. > > Rafael, could you do a defconfig-ish x86 build with and without CONFIG_PM, and post > the 'size vmlinux' comparison - so that we can see the size difference? We make some > things CONFIG_EXPERT configurable just to enable folks who *really* want to cut down > on kernel size to configure it out. For 2.6.38-rc4, x86_64, CONFIG_NR_CPUS=4: size vmlinux text data bss dec hex filename 6553910 3555020 9994240 20103170 132c002 vmlinux with CONFIG_PM 6512652 3553116 9994240 20060008 1321768 vmlinux without CONFIG_PM 41258 1904 0 43162 delta That is big enough for me to care. Turning on CONFIG_PM also forces a few other options on: 295a296 > CONFIG_XEN_SAVE_RESTORE=y 422c423,431 < # CONFIG_PM is not set --- > CONFIG_PM=y > # CONFIG_PM_DEBUG is not set > CONFIG_PM_SLEEP_SMP=y > CONFIG_PM_SLEEP=y > # CONFIG_SUSPEND is not set > # CONFIG_HIBERNATION is not set > # CONFIG_PM_RUNTIME is not set > CONFIG_PM_OPS=y > # CONFIG_ACPI is not set 451,454c460 < CONFIG_CPU_IDLE=y < CONFIG_CPU_IDLE_GOV_LADDER=y < CONFIG_CPU_IDLE_GOV_MENU=y < # CONFIG_INTEL_IDLE is not set --- > # CONFIG_CPU_IDLE is not set > > Note that those usecases, even if they want a super-small kernel, might not care > about PM at all while they care about size: small boot kernels in ROMs, or simple > devices where CPU-idling implies deep low power mode, etc. > > So the vmlinux size comparisons would be needed really. If it's 5k nobody will care. > If it's 50k-100k that's borderline. In the other side of the scale we have the 1500+ > #ifdef CONFIG_PM lines strewn around the kernel source, and the frequent !PM build > breakages. > > Ingo -Frank -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
