Messages in this thread | | | Date | Mon, 18 Mar 2002 17:28:30 -0800 (PST) | From | Davide Libenzi <> | Subject | Re: 7.52 second kernel compile |
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On Mon, 18 Mar 2002, David S. Miller wrote:
> From: Cort Dougan <cort@fsmlabs.com> > Date: Mon, 18 Mar 2002 17:36:35 -0700 > > The structure of the program you suggested with more portable timing. > > Oh, just something like: > > > gettimeofday(&stamp1); > for (A MILLION TIMES) { > TLB miss; > } > gettimeofday(&stamp2);
This make the measure stable on my machine :
#define rdtsc(low) \ __asm__ __volatile__("rdtsc" : "=A" (low) : )
unsigned long long start, end;
rdtsc(start); access(buffer[i]); rdtsc(end);
processor : 0 vendor_id : AuthenticAMD cpu family : 6 model : 4 model name : AMD Athlon(tm) Processor stepping : 2 cpu MHz : 999.561 cache size : 256 KB fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 1 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov pat pse36 mmx fxsr syscall mmxext 3dnowext 3dnow bogomips : 1992.29
$ gcc -o tlb_test tlb_test.c
#APP rdtsc #NO_APP movl %eax, -24(%ebp) movl %edx, -20(%ebp) movl -4(%ebp), %eax addl -12(%ebp), %eax movl (%eax), %eax #APP rdtsc
11.89: 18 4.70: 20 81.90: 23
$ gcc -O2 -o tlb_test tlb_test.c
#APP rdtsc #NO_APP movl %edx, -28(%ebp) movl -24(%ebp), %edx movl %eax, -32(%ebp) movl (%esi,%edx), %ecx #APP rdtsc #NO_APP
87.70: 20 11.24: 25
- Davide
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