i think a lot of the slowdown comes from that linux was not
streamlined its userspace, but the userspace just got more and more
complicated and does tons of redundant stuff... what they did then
was not to fix userspace, but they optimized the kernel to cache
anything...
look at some typical syscall traces... tons of files are stat()ed...
multiple times... it opens unix domain sockets to talk to a not
existant ldap name service or something... tons of shared libraries
are loaded... and that is all before even your main() entry is gets
called...
linuxemu doesnt shortcut these things... i cant reuse the shared
library mmaps on exec ect... i think walks are not cached in plan9,
so you have to talk to your fileserver.
the syscall overhead is just one of the bottlenecks of linux emulation
and you would have to put tons of more crap in the kernel to get
mozilla or opera working... and even more to get it half as fast as
in linux.