__set_cyc2ns_scale

Name:__set_cyc2ns_scale

Proto:static void __set_cyc2ns_scale(unsigned long khz, int cpu, unsigned long long tsc_now)

Type:void

Parameter:

Type	Parameter	Name
unsigned long	khz
int	cpu
unsigned long long	tsc_now

129

ns_now = Accelerators for sched_clock()* convert from cycles(64bits) => nanoseconds (64bits)* basic equation:* ns = cycles / (freq / ns_per_sec)* ns = cycles * (ns_per_sec / freq)* ns = cycles * (10^9 / (cpu_khz * 10^3))* ns = cycles * (10^6 / cpu_khz)

136

clocks_calc_mult_shift( & cyc2ns_mul, & cyc2ns_shift, khz, NSEC_PER_MSEC, 0)

145

If cyc2ns_shift == 32 Then

146

cyc2ns_shift = 31

147

cyc2ns_mul >>= 1

150

cyc2ns_offset = ns_now - mul_u64_u32_shr(tsc_now, cyc2ns_mul, cyc2ns_shift)

153

c2n = per_cpu_ptr( & cyc2ns, cpu)

155

aw_write_seqcount_latch - redirect readers to even/odd copy*@s: pointer to seqcount_t* The latch technique is a multiversion concurrency control method that allows* queries during non-atomic modifications. If you can guarantee queries never

156

0 + 2*16 = 32 [0] = data

157

aw_write_seqcount_latch - redirect readers to even/odd copy*@s: pointer to seqcount_t* The latch technique is a multiversion concurrency control method that allows* queries during non-atomic modifications. If you can guarantee queries never

158

0 + 2*16 = 32 [1] = data

**Caller**
Name	Describe
set_cyc2ns_scale
cyc2ns_init_boot_cpu	Initialize cyc2ns for boot cpu

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