Suggestions on Avoiding syscall Overhead

Peter Jeremy peterjeremy at
Thu Apr 26 10:24:23 UTC 2007

On 2007-Apr-25 01:03:19 -0700, Suleiman Souhlal <ssouhlal at> 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

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


Peter Jeremy
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 187 bytes
Desc: not available
Url :

More information about the freebsd-current mailing list