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| author | Robert Mustacchi <rm@joyent.com> | 2019-01-15 01:26:05 +0000 |
|---|---|---|
| committer | Robert Mustacchi <rm@joyent.com> | 2019-02-08 14:33:06 +0000 |
| commit | 007d65bc4ff2f2e56cc6fae2335af27bf16d373f (patch) | |
| tree | 404cf5a488bfe79c09f1536280d10406fc68b81a /usr/src | |
| parent | 2a1fd0ffe121888d44fdec321c25b53dcfaa9118 (diff) | |
| download | illumos-gate-007d65bc4ff2f2e56cc6fae2335af27bf16d373f.tar.gz | |
10278 Prefer use of mwait on AMD Zen
Reviewed by: John Levon <john.levon@joyent.com>
Reviewed by: Jordan Hendricks <jordan.hendricks@joyent.com>
Approved by: Hans Rosenfeld <hans.rosenfeld@joyent.com>
Diffstat (limited to 'usr/src')
| -rw-r--r-- | usr/src/uts/i86pc/os/cpuid.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/usr/src/uts/i86pc/os/cpuid.c b/usr/src/uts/i86pc/os/cpuid.c index 0174eb4bbb..e4bd0c7c99 100644 --- a/usr/src/uts/i86pc/os/cpuid.c +++ b/usr/src/uts/i86pc/os/cpuid.c @@ -2458,13 +2458,14 @@ cpuid_pass1(cpu_t *cpu, uchar_t *featureset) #if !defined(__xpv) /* - * Do not use MONITOR/MWAIT to halt in the idle loop on any AMD - * processors. AMD does not intend MWAIT to be used in the cpu - * idle loop on current and future processors. 10h and future - * AMD processors use more power in MWAIT than HLT. - * Pre-family-10h Opterons do not have the MWAIT instruction. + * AMD has not historically used MWAIT in the CPU's idle loop. + * Pre-family-10h Opterons do not have the MWAIT instruction. We + * know for certain that in at least family 17h, per AMD, mwait + * is preferred. Families in-between are less certain. */ - idle_cpu_prefer_mwait = 0; + if (cpi->cpi_family < 0x17) { + idle_cpu_prefer_mwait = 0; + } #endif break; |