Ctest : Win32 + AVX2 fails virtually all cycles tests. #64624

New Issue

Ray molenkamp · 2019-05-14T22:02:41+02:00

Ray molenkamp commented

2019-05-14 22:02:41 +02:00

System Information
Operating system: Win32
Graphics card: N/A

Blender Version
Broken: Master X86 on an AVX2 cpu on windows (i have no test metrics yet on linux32 bit)
Worked: no idea

Short description of error

Cycles is really unhappy with the combination of X86 and AVX2, see attached testing report for details.CyclesTestReport.205.zip

When run on AVX beyond a handful few actually broken tests all pass.

Exact steps for others to reproduce the error
run test suite on x86 + AVX2

**System Information** Operating system: Win32 Graphics card: N/A **Blender Version** Broken: Master X86 on an AVX2 cpu on windows (i have no test metrics yet on linux32 bit) Worked: no idea **Short description of error** Cycles is really unhappy with the combination of X86 and AVX2, see attached testing report for details.[CyclesTestReport.205.zip](https://archive.blender.org/developer/F7037266/CyclesTestReport.205.zip) When run on AVX beyond a handful few actually broken tests all pass. **Exact steps for others to reproduce the error** run test suite on x86 + AVX2

Ray molenkamp commented

2019-05-14 22:02:41 +02:00

Added subscriber: @LazyDodo

Sergey Sharybin was assigned by Ray molenkamp

2019-05-14 22:08:02 +02:00

Ray molenkamp commented

2019-05-14 22:08:02 +02:00

think you had some ideas there, mind taking a peek?

Brecht Van Lommel commented

2019-05-15 00:28:48 +02:00

Added subscriber: @brecht

Brecht Van Lommel commented

2019-05-15 00:28:48 +02:00

Simply disabling AVX2 on x86 might work:

diff --git a/intern/cycles/util/util_system.cpp b/intern/cycles/util/util_system.cpp
index 0cd991c6231..6064701fcbc 100644
--- a/intern/cycles/util/util_system.cpp
+++ b/intern/cycles/util/util_system.cpp
@@ -299,9 +299,13 @@ bool system_cpu_support_avx()

 bool system_cpu_support_avx2()
 {
+#  if defined(__x86_64__) || defined(_M_X64)
   CPUCapabilities &caps = system_cpu_capabilities();
   return caps.sse && caps.sse2 && caps.sse3 && caps.ssse3 && caps.sse41 && caps.avx && caps.f16c &&
          caps.avx2 && caps.fma3 && caps.bmi1 && caps.bmi2;
+#  else
+  return false;
+#  endif
 }
 #else

Simply disabling AVX2 on x86 might work: ``` diff --git a/intern/cycles/util/util_system.cpp b/intern/cycles/util/util_system.cpp index 0cd991c6231..6064701fcbc 100644 --- a/intern/cycles/util/util_system.cpp +++ b/intern/cycles/util/util_system.cpp @@ -299,9 +299,13 @@ bool system_cpu_support_avx() bool system_cpu_support_avx2() { +# if defined(__x86_64__) || defined(_M_X64) CPUCapabilities &caps = system_cpu_capabilities(); return caps.sse && caps.sse2 && caps.sse3 && caps.ssse3 && caps.sse41 && caps.avx && caps.f16c && caps.avx2 && caps.fma3 && caps.bmi1 && caps.bmi2; +# else + return false; +# endif } #else ```

Ray molenkamp commented

2019-05-15 01:07:40 +02:00

I'm still on Ivy Bridge so can't easily test this. patch looks like it would work though.

Sergey Sharybin commented

2019-05-15 09:23:49 +02:00

I would keep the system utilities as-is and will not do a kernel-specific tweaks in there. Would prefer something like this with a comment that 32bit kernel doesn't do vectorization and hence can not advertise BVH8:

P974: (An Untitled Masterwork)

diff --git a/intern/cycles/device/device_cpu.cpp b/intern/cycles/device/device_cpu.cpp
index 837a8186064..dc9adcb1537 100644
--- a/intern/cycles/device/device_cpu.cpp
+++ b/intern/cycles/device/device_cpu.cpp
@@ -332,9 +332,11 @@ class CPUDevice : public Device {
     if (DebugFlags().cpu.has_sse2() && system_cpu_support_sse2()) {
       bvh_layout_mask |= BVH_LAYOUT_BVH4;
     }
+#if defined(__x86_64__) || defined(_M_X64)
     if (DebugFlags().cpu.has_avx2() && system_cpu_support_avx2()) {
       bvh_layout_mask |= BVH_LAYOUT_BVH8;
     }
+#endif
 #ifdef WITH_EMBREE
     bvh_layout_mask |= BVH_LAYOUT_EMBREE;
 #endif /* WITH_EMBREE */

I would keep the system utilities as-is and will not do a kernel-specific tweaks in there. Would prefer something like this with a comment that 32bit kernel doesn't do vectorization and hence can not advertise BVH8: [P974: (An Untitled Masterwork)](https://archive.blender.org/developer/P974.txt) ``` diff --git a/intern/cycles/device/device_cpu.cpp b/intern/cycles/device/device_cpu.cpp index 837a8186064..dc9adcb1537 100644 --- a/intern/cycles/device/device_cpu.cpp +++ b/intern/cycles/device/device_cpu.cpp @@ -332,9 +332,11 @@ class CPUDevice : public Device { if (DebugFlags().cpu.has_sse2() && system_cpu_support_sse2()) { bvh_layout_mask |= BVH_LAYOUT_BVH4; } +#if defined(__x86_64__) || defined(_M_X64) if (DebugFlags().cpu.has_avx2() && system_cpu_support_avx2()) { bvh_layout_mask |= BVH_LAYOUT_BVH8; } +#endif #ifdef WITH_EMBREE bvh_layout_mask |= BVH_LAYOUT_EMBREE; #endif /* WITH_EMBREE */ ```

Ray molenkamp commented

2019-05-15 17:01:48 +02:00

I tested sergeys patch with intels sde emulating an avx2 core (test took, 1.5 hours.. yikes..) and it makes most of the tests pass now (the failing ones seem unrelated to this issue and fail on avx/sse as well)

blender-admin commented

2019-05-16 11:51:25 +02:00

This issue was referenced by blender/cycles@7a497fb71a

This issue was referenced by blender/cycles@7a497fb71ae1113205981249b3d968f419e31e3e

blender-admin commented

2019-05-16 11:51:25 +02:00

This issue was referenced by fced0f0437

This issue was referenced by fced0f043786bf54fa1e2bc4a78c91883fee8ed8

Sergey Sharybin commented

2019-05-16 11:52:54 +02:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2019-05-16 11:52:54 +02:00

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Ctest : Win32 + AVX2 fails virtually all cycles tests. #64624