On Wed, Jul 27, 2016 at 09:06:44AM -0400, Bruce Ashfield wrote: > On 2016-07-27 08:28 AM, Ed Bartosh wrote: > >Hi Bruce, > > > >Thank you for your suggestion to experiment with configuration options! > > > >>On 2016-07-26 10:32 AM, Ed Bartosh wrote: > >>>Hi all, > >>> > >>>We've noticed quite big increase of core-image-minimal build time caused > >>>by commit > >>>d55b7650d305ffad953dd36595ee6b9aa8df5a72 linux-yocto: Enablei > >>>debug/printk.scc KERNEL_FEATURE on qemuall machines. > >>> > >> > >>That commit only enables the following options: > >> > >>CONFIG_PRINTK=y > >>CONFIG_PRINTK_TIME=y > >> > >>CONFIG_EARLY_PRINTK=y > >> > >>CONFIG_EARLY_PRINTK_DBGP=y > >>CONFIG_EARLY_PRINTK_EFI=y > >>CONFIG_TTY_PRINTK=y > >> > >>And yes, that will add some size to the kernel, but I'm not seeing > >>similar size increases here. > >> > >>If you take a look through the kernel source and build, there are > >>relatively few additions to the actual kernel build that change > >>based on those options, and most of them are runtime changes versus > >>build-time changes. > >> > > > >The actuall difference in configuration is bigger as far as I can see: > >$ diff -u > >../build-kernel/tmp/work/qemux86_64-poky-linux/linux-yocto/4.4.14+gitAUTOINC+4800a400d5_8361321fec-r0/image/boot/config-4.4.14-yocto-standard > >tmp/work/qemux86_64-poky-linux/linux-yocto/4.4.14+gitAUTOINC+4800a400d5_8361321fec-r0/image/boot/config-4.4.14-yocto-standard > > | grep '^+C' > >+CONFIG_CONSOLE_POLL=y > >+CONFIG_PRINTK_TIME=y > >+CONFIG_DEBUG_INFO=y > >+CONFIG_DEBUG_KERNEL=y > >+CONFIG_SCHED_DEBUG=y > >+CONFIG_DEBUG_PREEMPT=y > >+CONFIG_KGDB=y > >+CONFIG_KGDB_SERIAL_CONSOLE=y > >+CONFIG_KGDB_LOW_LEVEL_TRAP=y > >+CONFIG_KGDB_KDB=y > >+CONFIG_KDB_DEFAULT_ENABLE=0x1 > >+CONFIG_KDB_KEYBOARD=y > >+CONFIG_KDB_CONTINUE_CATASTROPHIC=0 > >+CONFIG_EARLY_PRINTK_DBGP=y > >+CONFIG_EARLY_PRINTK_EFI=y > >+CONFIG_DEBUG_RODATA=y > >+CONFIG_DEBUG_RODATA_TEST=y > >+CONFIG_X86_DEBUG_FPU=y > > > >I guess the reason of this is that printk.scc includes debug-kernel.scc, > >which brings more config options: > >CONFIG_DEBUG_KERNEL=y > >CONFIG_DEBUG_INFO=y > >CONFIG_DEBUG_PREEMPT=y > > > >That probably explains the difference in kernel size and compile time. > > > > Yup. > > >After removing 'include debug-kernel.scc' the difference in > >configuration became more reasonable: > >+CONFIG_PRINTK_TIME=y > >+CONFIG_EARLY_PRINTK_DBGP=y > >+CONFIG_EARLY_PRINTK_EFI=y > > > >And the size of kernel and modules became almost the same as before > >enabling printk feature. > > > >Considering that the rest of the options from printk.scc don't appear in > >the result configuration even if debug-kernel.scc is included I hope > >it should be ok to remove 'include debug-kernel.scc' from printk.scc. > > > >Does it make sense for you? > > It does to me. Since we actually have a "developer" kernel type that > is intended for this purpose. Anything that we add to the standard > kernel type should be more surgical. >
Looking at guilty commit https://git.yoctoproject.org/cgit/cgit.cgi/yocto-kernel-cache/commit/?h=yocto-4.4&id=fd8d90ca69f53d425fdb34fc9a9debac1d0c5f52 I'd say that the rest of scc files should be also tested the same way. We may not need to enable all 3 CONFIG_DEBUG options for each of them. -- Regards, Ed -- _______________________________________________ Openembedded-core mailing list Openembedded-core@lists.openembedded.org http://lists.openembedded.org/mailman/listinfo/openembedded-core
