Re: [9fans] LinuxEMU

[cinap_lenrek@gmx.de]

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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.

just keep plan9 small and simple.  you dont want to maintain something
as complex and optimized-to-death as the full linux kernel with all
that caching and read aheading and 100 different stat syscalls.

we shouldnt be araid of writing new programs and dont concentrate on
keeping the legacy alive so mutch.  you can even run linux/major os
side by side with plan9 these days on virtual machines.  and this gets
cheaper every day without doing anything.  in fact this seems to be
what most people on iwp9 where doing.  (on ther fucking macbooks)

;-)

--
cinap

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The SVN thread got me thinking that I had remembered seeing Ron post
something about what I thought was an in-kernel LinuxEMU that got a little
better performance on plan 9.

Is this true?  I know the currently LinuxEMU is pretty impressive and can
run a large range of programs (Web browsers even!), but that sometimes the
performance is a little bit less than what might be desired.   I believe
this was due to extra system call overheads for each linux kernel call.

Does anyone know what I'm talking about or am I just babbling away here?

Dave

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