diff options
| author | James Almer <jamrial@gmail.com> | 2015-05-27 03:30:20 -0300 |
|---|---|---|
| committer | James Almer <jamrial@gmail.com> | 2015-05-27 03:31:11 -0300 |
| commit | c312bfac4c8ac1ac55d6648fd6eb36db436100f3 (patch) | |
| tree | 23605a4f16f399152f08edc21c21a46989a8d457 /libavutil/x86 | |
| parent | 52fc3e372f8ed4de5735abed1f7f7569fe37b023 (diff) | |
x86/cpu: add AV_CPU_FLAG_AVXSLOW flag
Reviewed-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: James Almer <jamrial@gmail.com>
Diffstat (limited to 'libavutil/x86')
| -rw-r--r-- | libavutil/x86/cpu.c | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/libavutil/x86/cpu.c b/libavutil/x86/cpu.c index 2b62e92479..7a5d4e6a3a 100644 --- a/libavutil/x86/cpu.c +++ b/libavutil/x86/cpu.c @@ -167,6 +167,7 @@ int ff_get_cpu_flags_x86(void) if (ext_caps & (1 << 22)) rval |= AV_CPU_FLAG_MMXEXT; + if (!strncmp(vendor.c, "AuthenticAMD", 12)) { /* Allow for selectively disabling SSE2 functions on AMD processors with SSE2 support but not SSE4a. This includes Athlon64, some Opteron, and some Sempron processors. MMX, SSE, or 3DNow! are faster @@ -174,9 +175,19 @@ int ff_get_cpu_flags_x86(void) AV_CPU_FLAG_SSE2 and AV_CPU_FLAG_SSE2SLOW are both set in this case so that SSE2 is used unless explicitly disabled by checking AV_CPU_FLAG_SSE2SLOW. */ - if (!strncmp(vendor.c, "AuthenticAMD", 12) && - rval & AV_CPU_FLAG_SSE2 && !(ecx & 0x00000040)) { - rval |= AV_CPU_FLAG_SSE2SLOW; + if (rval & AV_CPU_FLAG_SSE2 && !(ecx & 0x00000040)) + rval |= AV_CPU_FLAG_SSE2SLOW; + + /* Similar to the above but for AVX functions on AMD processors. + This is necessary only for functions using YMM registers on Bulldozer + based CPUs as they lack 256-bits execution units. SSE/AVX functions + using XMM registers are always faster on them. + AV_CPU_FLAG_AVX and AV_CPU_FLAG_AVXSLOW are both set so that AVX is + used unless explicitly disabled by checking AV_CPU_FLAG_AVXSLOW. + TODO: Confirm if Excavator is affected or not by this once it's + released, and update the check if necessary. Same for btver2. */ + if (family == 0x15 && (rval & AV_CPU_FLAG_AVX)) + rval |= AV_CPU_FLAG_AVXSLOW; } /* XOP and FMA4 use the AVX instruction coding scheme, so they can't be |