Suggestions on Avoiding syscall Overhead

[Peter Jeremy]

On 2007-Apr-25 01:03:19 -0700, Suleiman Souhlal <ssouhlal at freebsd.org> wrote:
>IMHO, the main usage of the global readonly page is (apart from  
>faster gettimeofday and similar) is that you can put the syscall  
>entry function in it, and have the kernel choose at boot the most  
>efficient method (INT 0x80 or SYSENTER/SYSCALL) based on what the CPU  
>supports, while still having binaries that run everywhere.

That's a nice idea.  The only downside I see is that it means the
page would need to be executable.  I would prefer not to have
data areas executable - even if they are read-only.

I think that FreeBSD should make more use of CPU-specific coding to
enhance performance.  Maybe even something along the lines of Solaris
where linking to libc implicitly links to a CPU-specific .so if it
exists.

>Similarly, I don't think getuid, geteuid, getpid,getgid, getegid,  
>getpgrp are used enough to justify the work.

Likewise.

-- 
Peter Jeremy
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