Date: Wed, 13 Dec 2006 01:59:23 -0800 (PST) From: ranjith kumar <ranjith_kumar_b4u@yahoo.com> To: freebsd-ia32@freebsd.org Subject: writing to performance event select registers Message-ID: <75870.6526.qm@web58615.mail.re3.yahoo.com>
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Hi,
I want to measure number of last level cache
misses in Pentium 4 processor. In IA-32 programmers
manuals it was given that there are (architectural=
same across all IA-32 processors)perfomance monitoring
counters starting at address 0c1H and
performance_event_select registers starting at address
186H.
1) When I tried to run a kernel module to write some
value in performance event select register (with
address 186H) by wrmsr instruction, the system is
hanging.Why?
The program is :
#include <linux/module.h> /* Needed by all modules */
#include <linux/kernel.h> /* Needed for KERN_INFO */
//#include<xmmintrin.h>
int i,j,k=0;
unsigned int xx,yy,xx1,yy1,xx2,yy2;
unsigned int t1,t2,t3,t4,BIG=0xffffffff;
int init_module(void)
{
asm volatile (" movl $0x186, %%ecx;"
" movl $0x0, %%edx;"
" movl $0x0009412E, %%eax;"
" wrmsr;"
:
:
:"%eax","%edx","%ecx");
printk(KERN_INFO " Initially %u=t1 %u=t2 %u=t3 %u=t4
\n",t1,t2,t3,t4);
return 0;
}
void cleanup_module(void)
{
printk(KERN_INFO "Goodbye world \n");
}
-------------------------------------------------------
Thanks in advane.
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