Re: [Xen-devel] Enhancing Xen's Kconfig infrastructure to support tailored solutions

[P S <pairspace@xxxxxxxxx>]

On Feb 19, 2019, at 14:13, Stefano Stabellini <sstabellini@xxxxxxxxxx> wrote:

On Mon, 18 Feb 2019, Lars Kurth wrote:

     On 18 Feb 2019, at 12:16, George Dunlap <george.dunlap@xxxxxxxxxx> wrote:

On 2/18/19 12:11 PM, George Dunlap wrote:

     On 2/18/19 12:01 PM, Andrew Cooper wrote:

           On 18/02/2019 11:57, Wei Liu wrote:

                 On Mon, Feb 18, 2019 at 11:53:15AM +0000, Lars Kurth wrote:

                             On 18 Feb 2019, at 11:30, George Dunlap

                             <george.dunlap@xxxxxxxxxx> wrote:

                             On 2/18/19 11:23 AM, Wei Liu wrote:

                                   On Mon, Feb 18, 2019 at 11:17:56AM +0000, Lars

                                   Kurth wrote:

                                         Thank you Wei. It's interesting though

                                         that the full vs HVM only is almost

                                         identical in terms of SLOC's

                                         Lars

                                   The cloc target counts the files in the dependency

                                   graph generated by

                                   make.

                       Do we know for sure that CLOC counts everything in a file or does it honour

                       the pre-processor settings?

                 We certainly don't feed any preprocessor defines to it. I doubt it

                 understand C to that level of details anyway.

           LoC isn't a fantastic metric under any circumstance.

           Bigger code is definitely better, if the reason it is bigger is because

           it is because it is formatted for readability/clarity etc.

           Attempting to optimise for smaller LoC, other than making entire

           functional areas optional, is usually short sighted.

     For instance, we could probably decrease the LoC by nearly 20k by

     changing the style not to give the opening bracket its own line:

     $ find . -name '*.c' | xargs grep '^[[:space:]]*{' | wc -l

     19896

     $ find . -name '*.[ch]' | xargs grep '^[[:space:]]*{' | wc -l

     21847

This is hypervisor only BTW (run from xen.git/xen).

It is a bit mind-boggling to think that there are more open brackets in

the Xen code base than there is PV-specific code. O_o

As we have the same coding conventions across hypervisor code, that shouldn't make a difference

This is amazing, in a terrible kind of way: all our numbers will be
inflated by 20K!! For Xen on Arm is almost 50%! I am half-thinking we
should add xargs grep '^[[:space:]]*{' to the make cloc target.

UCC (Unified Code Count) [1] can measure/diff logical SLOC for several languages.

Rich

[1] Papers 

http://csse.usc.edu/TECHRPTS/2007/usc-csse-2007-737/usc-csse-2007-737.pdf

http://csse.usc.edu/csse/event/2012/COCOMO/presentations/TOR-2010(3906)-72_Library.pdf

http://www.nguyenvvu.net/wp-content/uploads/2015/07/UCC_Tool_Description.pdf

[2] Source

http://csse.usc.edu/ucc_new/wordpress/2018/07/26/ucc-version-2018-07/

[3] Build

g++ ./src/*.cpp -o UCC -std=c++0x -DUNIX -O3

[4] Run

UCC -dir xen *.c -outdir report

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