"Igor Shmukler" shmukler@mail.ru writes:
But did anyone provide a solution? Surely you can point us to the Utah and UW papers which describe ipc performance comparable to L3/L4 ipc performance and where published before 1993. The program committee of the 93 SOSP surely thought otherwise and the audience was "shocked" when Jochen presented its 10-fold increase in IPC performance (l3 compared to Mach). The first thing Brian Ford did was asking Jochen for a copy of L3 to be able to verify the results (It was quite funny since L3 had a really strange user land and was mostly in German so Jochen had to coach Brian through the installation process).
Well obvious solution to Mach's problems is critical path optimizations.
wow, /me wonders why no-one ever thought about that...
that since l4 took almost everything out of the kernel, memory management could have been evicted as well (like Eros micro kernel does), then you may need to get offended.
You don't mean that Eros allows user level processes to directly manipulate kernel page tables? You are kidding, aren't you?
Well, I was talking about "First class flexpage-based address spaces" paper presented in by Shapiro in(around) 2000.
(Unfortunatly I was only able to browse the text version provided by google since the Server providing the post script version is down)
And? Did anybody implemement it? Eros doesn't use it...
http://www.eros-os.org/pipermail/eros-arch/2002-July/003425.html
Eros does even more memory management work inside the kernel then L4. If l4 catches a page fault it directly sends a message to the pager. Eros first tries to parse the capability tree to check whether there is a mapping present which isn't in its hardware page table and only if it finds no mapping it invokes the user level page fault handler.
If basic assertation is "microkernel is only to provide enough protection so that applications can provide abstractions", then resource allocation may be safely moved out of microkernel. Correct me when I am wrong.
Suggest an alternative way to implement address spaces and and everybody will listen.
Regards, Jean