cvs commit: src/share/man/man4 Makefile cpuctl.4 src/sys/amd64/amd64 support.S src/sys/amd64/conf NOTES src/sys/amd64/include cpufunc.h specialreg.h src/sys/conf files.amd64 files.i386 src/sys/dev/cpuctl cpuctl.c ...

[Stanislav Sedov]

On Fri, 8 Aug 2008 21:51:33 +0300
Kostik Belousov <kostikbel at gmail.com> mentioned:

> > 
> > You can achieve that now with cpuset. :)  (See my ping-pong test program 
> > recently which used cpuid to fetch the APIC ID to test for ping-ponging in 
> > the scheduler.)
> 
> If this is a backout request (for cpuid functionality) then we will do it.
> 
> But I considered it much easier and cleaner to do
> 	fd = open("/dev/cpuctlN", O_RDWR);
> 	ioctl(fd, CPUCTL_CPUID, &x);
> 	if (x.y)
> 		ioctl(fd, CPUCTL_WRMSR, ...);
> 	close(fd);
> then
> 	fd = open("/dev/cpuctlN", O_RDWR);
> 	cpuset(...); /* bind to cpu */
> 	__asm__("cpuid" : =0 (x));
> 	if (x.y)
> 		ioctl(fd, CPUCTL_WRMSR, ...);
> 	cpuset(...); /* restore prev mask */
> 	close(fd);
> 

One of the reasons to leave the cpuid functionality, present in
sysutils/devcpu, in cpuctl(4) was the fact, the software that
is supposed to use wrmsr/rdmsr calls, also usually perform
cpuid checks as well, and it will be clean to provide access to
all of this via a single interface.

-- 
Stanislav Sedov
ST4096-RIPE
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