12 Dec
2022
12 Dec
'22
3:09 a.m.
On 12/11/22, Bakul Shah <bakul(a)iitbombay.org> wrote:
Agree that clear code is preferable to complicated code. But in practice
people sacrifice clarity for performance improvement all the time. Look
at the kernel code of any modern os. Everybody pays lip service to this
but most anything other than toy programs ends up getting needlessly
complicated over time. As an example, building "Unix as a service" as
user processes on top of a small microkernel could provide the same
functionality using much clearer and much less code but it would be
slower so we don't do it. Plan9 sort of went in that direction and it
is much simpler (but that could also be because it is not hacked on so
much).
It's not necessarily true that microkernels are significantly slower.
They mostly got that reputation because of Mach and kernels like it
with their heavyweight IPC. Lightweight microkernels like QNX and the
L4 family generally have significantly better performance (in fact,
QNX 4 outperformed SysV/386 back in the 90s on certain benchmarks, and
a proof-of-concept network driver on a current version of seL4 is
significantly faster than a Linux network driver).