Performance issues due to the microkernel/multi-server system architecture?
IRC, freenode, #hurd, 2011-07-26
< CTKArcher> I read that, because of its microkernel+servers design, the hurd was slower than a monolithic kernel, is that confirmed ? < youpi> the hurd is currently slower than current monolithic kernels, but it's not due to the microkernel + servers design < youpi> the microkernel+servers design makes the system call path longer < youpi> but you're bound by disk and network speed < youpi> so the extra overhead will not hurt so much < youpi> except dumb applications keeping doing system calls all the time of course, but they are usually considered bogus < braunr> there may be some patterns (like applications using pipes extensively, e.g. git-svn) which may suffer from the design, but still in an acceptable range < CTKArcher> so, you are saying that disk and network are more slowing the system than the longer system call path and because of that, it wont really matter ? < youpi> braunr: they should sitll be fixed because they'll suffer (even if less) on monolithic kernels < youpi> CTKArcher: yes < braunr> yes < CTKArcher> mmh < youpi> CTKArcher: you might want to listen to AST's talk at fosdem 10 iirc, about minix < youpi> they even go as far as using an IPC for each low-level in/out < youpi> for security < braunr> this has been expected for a long time < braunr> which is what motivated research in microkernels < CTKArcher> I've already downloaded the video :) < youpi> and it has been more and more true with faster and faster cpus < braunr> but in 95, processors weren't that fast compared to other components as they are now < youpi> while disk/mem haven't evovled so fast