Messages in this thread | | | Date | Sat, 13 Jun 2015 10:57:59 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v2 13/17] x86/tsc: Rename native_read_tsc() to rdtsc_unordered() |
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On Fri, Jun 12, 2015 at 04:44:53PM -0700, Andy Lutomirski wrote: > Now that there is no paravirt TSC, the "native" is inappropriate. > The fact that rdtsc is not ordered can catch people by surprise, so > call it rdtsc_unordered(). > > Signed-off-by: Andy Lutomirski <luto@kernel.org>
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> @@ -109,7 +109,16 @@ notrace static inline int native_write_msr_safe(unsigned int msr, > extern int rdmsr_safe_regs(u32 regs[8]); > extern int wrmsr_safe_regs(u32 regs[8]); > > -static __always_inline unsigned long long native_read_tsc(void) > +/** > + * rdtsc_unordered() - returns the current TSC without ordering constraints > + * > + * rdtsc_unordered() returns the result of RDTSC as a 64-bit integer. The > + * only ordering constraint it supplies is the ordering implied by > + * "asm volatile": it will put the RDTSC in the place you expect. The > + * CPU can and will speculatively execute that RDTSC, though, so the > + * results can be non-monotonic if compared on different CPUs. > + */ > +static __always_inline unsigned long long rdtsc_unordered(void)
I like the rdtsc_ordered() thing because it wraps the barrier and people cannot just forget it. But let's call this not rdtsc_unordered() but simply
rdtsc()
The "_unordered" suffix is unnecessary IMO since this function is a simple wrapper around the hw insn and we do that naming scheme with all such wrappers.
-- Regards/Gruss, Boris.
ECO tip #101: Trim your mails when you reply. --
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