How to do it...

To enable the collection of statistics, your project needs to inherit the buildstats class by adding it to USER_CLASSES in your conf/local.conf file. By default, the fsl-community-bsp build project is configured to enable them.

USER_CLASSES ?= "buildstats"

You can configure the location of these statistics with the BUILDSTATS_BASE variable, and by default it is set to the buildstats folder in the tmp directory under the build directory (tmp/buildstats).

The buildstats folder contains a folder per image with the build stats under a timestamp folder. Under it will be a subdirectory per package in your built image, and a build_stats file that contains:

How it works...

The accuracy of the data depends on the download directory, DL_DIR, and the shared state cache directory, SSTATE_DIR, existing on the same partition or volume, so you may need to configure them accordingly if you are planning to use the build data.

An example build-stats file looks like the following:

Host Info: Linux agonzal 3.13.0-35-generic #62-Ubuntu SMP Fri Aug 15 01:58:42 UTC 2014 x86_64 x86_64
Build Started: 1411486841.52
Uncompressed Rootfs size: 6.2M  /opt/yocto/fsl-community- bsp/wandboard-quad/tmp/work/wandboard_quad-poky-linux- gnueabi/core-image-minimal/1.0-r0/rootfs
Elapsed time: 2878.26 seconds
CPU usage: 51.5%
EndIOinProgress: 0
EndReadsComp: 0
EndReadsMerged: 55289561
EndSectRead: 65147300
EndSectWrite: 250044353
EndTimeIO: 14415452
EndTimeReads: 10338443
EndTimeWrite: 750935284
EndWTimeIO: 816314180
EndWritesComp: 0
StartIOinProgress: 0
StartReadsComp: 0
StartReadsMerged: 52319544
StartSectRead: 59228240
StartSectWrite: 207536552
StartTimeIO: 13116200
StartTimeReads: 8831854
StartTimeWrite: 3861639688
StartWTimeIO: 3921064032
StartWritesComp: 0

These disk statistics come from the Linux kernel disk I/O stats (https://www.kernel.org/doc/Documentation/iostats.txt). The different elements are explained here:

IOinProgress: This is the total number of I/Os in progress when reading /proc/diskstats

And inside each package, we have a list of tasks; for example, for ncurses-5.9-r15.1, we have the following tasks:

Each one of them contain, in the same format as earlier, the following:

There's more...

You can also obtain a graphical representation of the data using the pybootchartgui.py tool included in the Poky source. From your project's build folder, you can execute the following command to obtain a bootchart.png graphic in /tmp:

$ ../sources/poky/scripts/pybootchartgui/pybootchartgui.py tmp/buildstats/core-image-minimal-wandboard-quad/ -o /tmp