Moving the kernel to modern C [LWN.net]

Moving the kernel to modern C

Posted Mar 3, 2022 22:19 UTC (Thu) by Wol (subscriber, #4433)
In reply to: Moving the kernel to modern C by dvdeug
Parent article: Moving the kernel to modern C

> In response to the statement that sometimes a Phillips head screwdriver is useful? If you don't believe that OO is useful for GUIs, point to alternatives and explain why OO languages are so popular for GUIs. KDE was done in C++ back before libstdc++ existed.

Except that this article is not about GUIs. Maybe it should be - why do we keep on having to buy newer, faster computers just to stop the guis slowing everything down? Do we really want to let that bloat into the kernel - pretty much bringing our super-fast new CPUS to a grinding halt ...

Cheers,
Wol

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Moving the kernel to modern C

Posted Mar 3, 2022 22:49 UTC (Thu) by dvdeug (guest, #10998) [Link] (2 responses)

This subthread started with a generalized bashing of OO languages, which is why a mention of where OO languages are useful came up.

I'd be interested to see good measurements of why modern GUIs are so much slower; I'm curious if once you compensate for the increase in screen size and the increase in data sizes, if they really are all that much slower.

Moving the kernel to modern C

Posted Mar 3, 2022 23:54 UTC (Thu) by Wol (subscriber, #4433) [Link] (1 responses)

I thought it started with a suggestion that OO languages (C++) be used in the kernel.

In which case, OO-bashing is justified. OO *IS* useful, but in the kernel when a few extra bytes of object code can cost you dearly in page faults etc, those faults are pretty fatal for the concept. THAT was the purpose of the bashing ...

Cheers,
Wol

Moving the kernel to modern C

Posted Mar 4, 2022 9:42 UTC (Fri) by mpr22 (subscriber, #60784) [Link]

The kernel embraced the size overheads of OO back in the 1990s, and C++'s OO model is just as much "pay for what you use" as the one the kernel uses.

If a class has no virtual members, it doesn't need a function table and doesn't have function-pointer dispatch overheads.

If it has some virtual members, only the members that are virtual have to be identified in the function table and called through function pointers.