mirror/libcpuid
1
0
Fork 0
mirror of https://github.com/anrieff/libcpuid synced 2025-10-13 11:10:39 +00:00
Code Issues Releases Wiki Activity

A small correction to account for the non-loop instructions in busy_sse_loop()

Browse source 
git-svn-id: https://svn.code.sf.net/p/libcpuid/code/HEAD/libcpuid@82 3b4be424-7ac5-41d7-8526-f4ddcb85d872
This commit is contained in:
Veselin Georgiev 2010-04-20 09:59:12 +00:00
commit b922a5b29c
1 changed files with 6 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

9
libcpuid/rdtsc.c
View file

@ -243,14 +243,15 @@ int cpu_clock_by_ic(int millis, int runs)
int max_value = 0, cur_value, i, ri, cycles_inner, cycles_outer, c; int max_value = 0, cur_value, i, ri, cycles_inner, cycles_outer, c;
struct cpu_id_t* id; struct cpu_id_t* id;
uint64_t t0, t1, tl, hz; uint64_t t0, t1, tl, hz;
int num_instructions = 256000000; int num_instructions = 256;
int sse_multiplier = 1;
if (millis <= 0 || runs <= 0) return -2; if (millis <= 0 || runs <= 0) return -2;
id = get_cached_cpuid(); id = get_cached_cpuid();
if (!id || !id->flags[CPU_FEATURE_SSE]) return -1; if (!id || !id->flags[CPU_FEATURE_SSE]) return -1;
// //
if (!sse_is_128_bit(id)) { if (!sse_is_128_bit(id)) {
debugf(1, "SSE execution path is 64-bit\n"); debugf(1, "SSE execution path is 64-bit\n");
num_instructions *= 2; sse_multiplier = 2;
} else { } else {
debugf(1, "SSE execution path is 128-bit\n"); debugf(1, "SSE execution path is 128-bit\n");
} }
@ -278,7 +279,9 @@ int cpu_clock_by_ic(int millis, int runs)
} while (t1 - t0 < tl * (uint64_t) 8); } while (t1 - t0 < tl * (uint64_t) 8);
// cpu_Hz = cycles_inner * cycles_outer * 256 / (t1 - t0) * 1000000 // cpu_Hz = cycles_inner * cycles_outer * 256 / (t1 - t0) * 1000000
debugf(2, "c = %d, td = %llu\n", c, t1 - t0); debugf(2, "c = %d, td = %llu\n", c, t1 - t0);
hz = (uint64_t) cycles_inner * (uint64_t) cycles_outer * (uint64_t) c * (uint64_t) num_instructions / (t1 - t0); hz = ((uint64_t) cycles_inner * (uint64_t) num_instructions + 8) *
(uint64_t) cycles_outer * (uint64_t) sse_multiplier * (uint64_t) c * (uint64_t) 1000000
/ (t1 - t0);
cur_value = (int) (hz / 1000000); cur_value = (int) (hz / 1000000);
if (cur_value > max_value) max_value = cur_value; if (cur_value > max_value) max_value = cur_value;
} }