Re: [PATCH v2 0/2] x86/cpu/AMD: Make LFENCE a serializing instruction on AMD

2018-01-08 Thread Borislav Petkov
On Mon, Jan 08, 2018 at 04:09:12PM -0600, Tom Lendacky wrote: > To aid in speculation control, the LFENCE instruction will be turned into > a serializing instruction. There is less performance impact using LFENCE > in this way compared to MFENCE. > > With LFENCE now being a serializing instruction

Re: [PATCH v2 0/2] x86/cpu/AMD: Make LFENCE a serializing instruction on AMD

2018-01-08 Thread Dan Williams
On Mon, Jan 8, 2018 at 2:09 PM, Tom Lendacky wrote: > To aid in speculation control, the LFENCE instruction will be turned into > a serializing instruction. There is less performance impact using LFENCE > in this way compared to MFENCE. > > With LFENCE now being a serializing instruction, it can b

[PATCH v2 0/2] x86/cpu/AMD: Make LFENCE a serializing instruction on AMD

2018-01-08 Thread Tom Lendacky
To aid in speculation control, the LFENCE instruction will be turned into a serializing instruction. There is less performance impact using LFENCE in this way compared to MFENCE. With LFENCE now being a serializing instruction, it can be also used in rdtsc_ordered() in preference to MFENCE_RDTSC.