[OE-core] 2.7% build time regression caused by enabling debug/printk.scc KERNEL_FEATURE]
Ed Bartosh
ed.bartosh at linux.intel.com
Wed Jul 27 12:28:01 UTC 2016
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.
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?
> >Here are results of /usr/bin/time -v bitbake core-image-minimal for this
> >and previous commits:
> >
> >linux-yocto: Enable debug/printk.scc KERNEL_FEATURE on qemuall machines: d55b7650d305ffad953dd36595ee6b9aa8df5a72
> > Command being timed: "bitbake core-image-minimal"
> > User time (seconds): 14966.24
> > System time (seconds): 3829.23
> > Percent of CPU this job got: 1212%
> > Elapsed (wall clock) time (h:mm:ss or m:ss): 25:50.52
> > Average shared text size (kbytes): 0
> > Average unshared data size (kbytes): 0
> > Average stack size (kbytes): 0
> > Average total size (kbytes): 0
> > Maximum resident set size (kbytes): 917592
> > Average resident set size (kbytes): 0
> > Major (requiring I/O) page faults: 8105
> > Minor (reclaiming a frame) page faults: 628476540
> > Voluntary context switches: 26886617
> > Involuntary context switches: 2033535
> > Swaps: 0
> > File system inputs: 3160048
> > File system outputs: 78417720
> > Socket messages sent: 0
> > Socket messages received: 0
> > Signals delivered: 0
> > Page size (bytes): 4096
> > Exit status: 0
> >
> >commit: nativesdk-packagegroup-sdk-host: Add wayland-scanner to the SDK native toolchain: e833508075bcb8f2d1ccddcf46f579aea7a2ab1d
> > Command being timed: "bitbake core-image-minimal"
> > User time (seconds): 14526.89
> > System time (seconds): 3770.74
> > Percent of CPU this job got: 1193%
> > Elapsed (wall clock) time (h:mm:ss or m:ss): 25:33.44
> > Average shared text size (kbytes): 0
> > Average unshared data size (kbytes): 0
> > Average stack size (kbytes): 0
> > Average total size (kbytes): 0
> > Maximum resident set size (kbytes): 917792
> > Average resident set size (kbytes): 0
> > Major (requiring I/O) page faults: 8058
> > Minor (reclaiming a frame) page faults: 618283939
> > Voluntary context switches: 26538183
> > Involuntary context switches: 1859365
> > Swaps: 0
> > File system inputs: 3191584
> > File system outputs: 66411592
> > Socket messages sent: 0
> > Socket messages received: 0
> > Signals delivered: 0
> > Page size (bytes): 4096
> > Exit status: 0
> >
> >The total time (user time + system time) incresed by 2.72% which seems quite a lot.
> >
> >diff of tasks utime shows biggest difference in do_package* tasks. This is probably
> >due to increased size of packages:
> >
> >do_bundle_initramfs:utime: 21 | do_bundle_initramfs:utime: 32
> >do_compile:utime: 47 | do_compile:utime: 51
> >do_compile_kernelmodules:utime: 39 | do_compile_kernelmodules:utime: 42
> >do_configure:utime: 20 | do_configure:utime: 24
> >do_deploy:utime: 38 | do_deploy:utime: 35
> >do_fetch:utime: 25 | do_fetch:utime: 28
> >do_install:utime: 26 | do_install:utime: 22
> >do_kernel_checkout:utime: 21 | do_kernel_checkout:utime: 24
> >do_kernel_configcheck:utime: 21 | do_kernel_configcheck:utime: 21
> >do_kernel_configme:utime: 23 | do_kernel_configme:utime: 23
> >do_kernel_link_images:utime: 24 | do_kernel_link_images:utime: 22
> >do_kernel_metadata:utime: 25 | do_kernel_metadata:utime: 23
> >do_package:utime: 396 | do_package:utime: 378
> >do_packagedata:utime: 35 | do_packagedata:utime: 34
> >do_package_qa:utime: 460 | do_package_qa:utime: 492
> >do_package_write_rpm:utime: 431 | do_package_write_rpm:utime: 399
> >do_patch:utime: 25 | do_patch:utime: 25
> >do_populate_lic:utime: 30 | do_populate_lic:utime: 29
> >do_populate_sysroot:utime: 33 | do_populate_sysroot:utime: 30
> >do_shared_workdir:utime: 24 | do_shared_workdir:utime: 25
> >do_sizecheck:utime: 23 | do_sizecheck:utime: 21
> >do_strip:utime: 23 | do_strip:utime: 23
> >do_uboot_mkimage:utime: 25 | do_uboot_mkimage:utime: 24
> >do_unpack:utime: 21 | do_unpack:utime: 22
> >do_validate_branches:utime: 23 | do_validate_branches:utime: 24
> >
> >There is also quite big increase in consumed disk space by the kernel
> >and modules:
> >$ ls -lh ./tmp.bad/work/qemux86-poky-linux/linux-yocto/4.4.14+gitAUTOINC+4800a400d5_8361321fec-r0/image/boot/vmlinux-4.4.14-yocto-standard
> >-rw-r--r-- 1 ed ed 261M Jul 25 12:39 ./tmp.bad/work/qemux86-poky-linux/linux-yocto/4.4.14+gitAUTOINC+4800a400d5_8361321fec-r0/image/boot/vmlinux-4.4.14-yocto-standard
> >$ ls -lh ./tmp.prev/work/qemux86-poky-linux/linux-yocto/4.4.14+gitAUTOINC+4800a400d5_8361321fec-r0/image/boot/vmlinux-4.4.14-yocto-standard
> >-rw-r--r-- 1 ed ed 19M Jul 25 17:34 ./tmp.prev/work/qemux86-poky-linux/linux-yocto/4.4.14+gitAUTOINC+4800a400d5_8361321fec-r0/image/boot/vmlinux-4.4.14-yocto-standard
> >
> >$ ls -lh tmp.bad/deploy/images/qemux86/modules--4.4.14+git0+4800a400d5_8361321fec-r0-qemux86-20160725092744.tgz
> >-rw-rw-r-- 2 ed ed 99M Jul 25 12:39 tmp.bad/deploy/images/qemux86/modules--4.4.14+git0+4800a400d5_8361321fec-r0-qemux86-20160725092744.tgz
> >$ ls -lh tmp.prev/deploy/images/qemux86/modules--4.4.14+git0+4800a400d5_8361321fec-r0-qemux86-20160725105810.tgz
> >-rw-rw-r-- 1 ed ed 4.3M Jul 25 17:34 tmp.prev/deploy/images/qemux86/modules--4.4.14+git0+4800a400d5_8361321fec-r0-qemux86-20160725105810.tgz
> >
> >Any thoughts on this? Is it normal or it should be tested further and fixed?
>
> I'm not sure that this is related to the debug printk build, but
> anything that that could be increasing footprint and build time
> like that should be looked into.
>
> Without messing with the oe-core commit that enabled the feature, has
> someone done a build, gone into the kernel .config, disabled the options
> and then rebuilt ? I'd start there to rule out that the option is
> actually doing something that significant to the build itself.
>
> .. but I can't say much more than that, since as you can see by the
> commit, I'm not on the sign-off list, so I don't have all the background.
>
> Bruce
>
> >
> >--
> >Regards,
> >Ed
> >
>
> --
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--
--
Regards,
Ed
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