Re: Intel P6 vs P7 system call performance

[H. Peter Anvin]

Terje Eggestad wrote:
> what about:
> 
> int (*_vsyscall) (int, ...);
> _vsyscall = mmap(NULL, getpagesize(),  PROT_READ|PROT_EXEC,
> MAP_VSYSCALL, , ); 
> 
> or if you're afraid of running out of MAP_* flags:
> 
> fd = open("/dev/vsyscall", );
> _vsyscall = mmap(NULL, getpagesize(),  PROT_READ|PROT_EXEC, MAP_SHARED,
> fd, 0);
> 
> Then you can leisurely map it in just after the programs text segment. 
> 

Very ugly -- then the application has to do indirect calls.

	-hpa