On Tue, 25 Oct 2016, Alexey Makhalov wrote:
> no-vmw-sched-clock kernel parameter is added to switch back to the
> native_sched_clock() implementation.
You are not switching back. The parameter is used to disable the paravirt
sched clock.
> #ifdef CONFIG_PARAVIRT
> +static struct cyc2ns_data vmware_cyc2ns __ro_after_init;
> +
> +static int vmw_sched_clock __initdata = 1;
> +static __init int setup_vmw_sched_clock(char *s)
Please stop glueing a variable to a function w/o a new line between
them. It's just stopping the reading flow.
> +{
> + vmw_sched_clock = 0;
> + return 0;
> +}
> +early_param("no-vmw-sched-clock", setup_vmw_sched_clock);
> +
> +static unsigned long long vmware_sched_clock(void)
> +{
> + unsigned long long ns;
> +
> + ns = mul_u64_u32_shr(rdtsc(), vmware_cyc2ns.cyc2ns_mul,
> + vmware_cyc2ns.cyc2ns_shift);
> + ns -= vmware_cyc2ns.cyc2ns_offset;
> + return ns;
> +}
> +
> static void __init vmware_paravirt_ops_setup(void)
> {
> pv_info.name = "VMware";
> pv_cpu_ops.io_delay = paravirt_nop;
> +
> + if (vmware_tsc_khz && vmw_sched_clock) {
> + unsigned long long tsc_now = rdtsc();
> +
> + clocks_calc_mult_shift(&vmware_cyc2ns.cyc2ns_mul,
> + &vmware_cyc2ns.cyc2ns_shift,
> + vmware_tsc_khz,
> + NSEC_PER_MSEC, 0);
> + vmware_cyc2ns.cyc2ns_offset =
> + mul_u64_u32_shr(tsc_now, vmware_cyc2ns.cyc2ns_mul,
> + vmware_cyc2ns.cyc2ns_shift);
> +
> + pv_time_ops.sched_clock = vmware_sched_clock;
> + pr_info("vmware: using sched offset of %llu ns\n",
Please use pr_fmt instead of adding the prefix to every print.
Thanks,
tglx
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