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SubjectRe: [RFC][PATCH 6/6] x86_64: GENERIC_TIME based vsyscall code
Date
On Wednesday 09 August 2006 04:17, john stultz wrote:

> + cycle_t ret;
> + rdtscll(ret);


_sync


> +static cycle_t __vsyscall_fn vread_hpet(void)
> +{
> + return (cycle_t)readl((void *)fix_to_virt(VSYSCALL_HPET) + 0xf0);
> +}

64bit HPET?


> +extern struct vsyscall_gtod_data_t vsyscall_gtod_data;

No extern in .c please


> +static __always_inline int syscall_gtod(struct timeval *tv, struct timezone *tz)
> +{
> + int ret;
> +
> + asm volatile("syscall"

You eliminated the patching away of the syscall opcode? Please retain that.



> - tv->tv_sec = sec + usec / 1000000;
> - tv->tv_usec = usec % 1000000;
> + now = __vsyscall_gtod_data.clock.vread();
> +
> + base = __vsyscall_gtod_data.clock.cycle_last;
> + mask = __vsyscall_gtod_data.clock.mask;
> + mult = __vsyscall_gtod_data.clock.mult;
> + shift = __vsyscall_gtod_data.clock.shift;
> +
> + *tv = __vsyscall_gtod_data.wall_time_tv;
> +
> + } while (read_seqretry(&__vsyscall_gtod_data.lock, seq));

Do you have benchmarks on performance compared to the old code?

-Andi
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