How to properly debug crash with burst compiler?

Hey.
Everything is fine when Job executed without Burst, but if enabled, that's makes Unity crash instantly without any info in .log files or whatsoever.
It's about a week I'm trying to figure out what exactly is the reason of Unity Job system crashes in my case. I will try to describe the situation in detail.

I am using Job which is work with NativeList's and manage some data from meshes for me. Mentioned Job basically writes the data in loop into the "NativeList<Vector3>" from provided for Job "NativeArray<Vector3>", but with some offset and with some rotation, like this:

Code (CSharp):

1. for (int i = 0; i < meshesCount; i++)
2. {
3.    angle.y = meshRotation[i];
4.    rotation.eulerAngles = angle;
5.  
6.    for (int j = 0; j < vertexCount; j++)
7.    {
8.           vertices.Add((rotation * s_vertices[j) + offset[i]);
9.    }
10.  
11. }

Again, this code works fine without "[BurstCompiler]" attribute over Job. I also tryed to use NativeArray instead of NativeList, and also "float3" from Mathematics package instead of Vector3, but no luck - works only without Burst.

So at some point without having any error text I simply just comment out the code and check it line by line. I found out that calling eulerAngles cause of crash and what's funny not only that. After disabling everything about rotation - Job started working again. But if you run the Job several times, even if it is exactly the same way and with the same data - you also get crash. Ussually Job works only once before crash.

If you add to the list just some single regular "Vector3" - it's fine. If you do calculation like above - crash. If you do calculation in some temp variable is okay, but only if you not trying to add this to the list(or write in array) - then is crash, like this variable is something special about. Am I missing something? And when I do same calculation thing with any hardcoded values is also crashes.

So I wonder how to debug here everything and make Job work with burst. I also wonder what I'm missing and why Burst is acting like this. I don't see anything about in the documentation.

 

Enable Burst safety checks and other stuff inside Jobs/Burst/SafetyCheck.

The thing broke inside burst here is "Vector3". Burst only support anything inside new

math 

library not

Mathf

(all Vector3 stuff)

 

Thank you very much for your reply and pointing me towards math library. It was also nice to find documentation from package about that.
But please, can you tell me what could be wrong with this code bellow then? That would be also very kind of you.

Code (CSharp):

1. [BurstCompile]
2. private struct TestJob : IJob
3. {
4.     public NativeList<float3> vertex;
5.     public float3 rotator;
6.  
7.     public void Execute()
8.     {
9.         rotator.y = 1.5708f;
10.  
11.         float3 a = new float3(0, 0, 10);
12.         float3 b = new float3(0, 5, 0);
13.  
14.         vertex.Add(math.rotate(quaternion.Euler(rotator), a) + b);
15.     }
16. }

Expecting here result is ~10, 5, 0, which work's only without Burst, as I can see it's crash because of euler&rotate part, just a + b it's fine.

Also, returning to debug thing, I am still unable to get any error text in the log files or anything - enabling safety checks and other stuff there doesn't seem to change anything. I do understand that Burst is in development, but I'm fairly not sure I'm doing with it right.

I also found "JobsUtility.JobDebuggerEnabled" at "Unity.Jobs.LowLevel.Unsafe", but this also doesn't help to have something about. Curious what that applies to then.

 

It's not true. Vector3 works fine with burst, some Mathf stuff too, only things with static (exclude readonly\const) fields\properties not compatable with burst. Difference is math SIMD friendly and this why it's faster and better. Here fast sample, that it works fine with Mathf, Vector3 etc.

Code (CSharp):

1. [BurstCompile]
2. public struct SomeBurstedJob : IJob
3. {
4.     public NativeList<Quaternion> list;
5.     public Vector3 vector;
6.     public void Execute()
7.     {
8.         Quaternion a = new Quaternion();
9.         a.eulerAngles = vector;
10.         list.Add(a);
11.     }
12. }
13.  
14. ...
15.  
16.  
17. var list = new NativeList<Quaternion>(Allocator.TempJob);
18.         SomeBurstedJob test = new SomeBurstedJob()
19.         {
20.             vector = new Vector3(90, 0, 0),
21.             list   = list
22.         };
23.         test.Schedule().Complete();
24.         Debug.Log(list[0].eulerAngles);
25.         list.Dispose();

a.eulerAngles = vector.normalized;

vector = vector.normalized;

vector.y = Mathf.PI;

 

hm, I didn't know Vector3 function also work.
In my case, there are few times when Burst compile do some weird math and broke the game so I just stop using it all together.
@SiriusRU you might want to double check Package Manager if you have lastest burst or have infinite loop add for

public NativeList<float3> vertex

before write bug report
Also, Debug log not work inside Burst

 

Huh. Well, that's right - I am using last burst package version("1.0.0 preview6" to be exact), Unity 2018.3.9f1 version and there is no infinity loop for sure. I also not expecting "Debug.Log" to work in Job, but Burst were initially designed to give some info if something goes wrong and of course I'd like to know if I missing something about what is wrong here.

Oh.. So it's suppose to actually work in that case then??
I can see your result from the console clearly, but I copied your code and it's instant crash for me. To be honest, I'm kind of confused now what to do.

Update: Copied code actually working. But I still don't get it overall, like why is there crash.

 

Just for clarification - Show Error (red icon) enabled in console?

 

Yes, sure. But it's instant crash, so there is no chance to read console in Unity, I am using log files to read if there any info and it has nothing about crash or any error message. In the end there is only regular last Unity logs.

 

I slightly modified your code like this to slighly more fit what I'm doing

Spoiler

Code (CSharp):

1. var vertices = new NativeList<Vector3>(Allocator.TempJob);
2. SomeBurstedJob test = new SomeBurstedJob()
3. {
4.     vector = new Vector3(90, 0, 0),
5.     vertices = vertices,
6.     offset = new Vector3(7, 0, 0)
7. };
8.  
9. test.Schedule().Complete();
10. Debug.Log(vertices[0]);
11. vertices.Dispose();

Code (CSharp):

1. [BurstCompile]
2. public struct SomeBurstedJob : IJob
3. {
4.     public NativeList<Vector3> vertices;
5.     public Vector3             vector;
6.     public Vector3             offset;
7.  
8.     public void Execute()
9.     {
10.         Quaternion rotation = new Quaternion();
11.         rotation.eulerAngles = vector;
12.  
13.         Vector3 vertex = (rotation * new Vector3(0, 0, 10)) + offset;
14.  
15.         vertices.Add(vertex);
16.     }
17. }

And it's working fine like everything is okay.
But if, for example, use math and float3 instead to do same thing like this:

Spoiler

Code (CSharp):

1. var vertices = new NativeList<float3>(Allocator.TempJob);
2. SomeBurstedJob test = new SomeBurstedJob()
3. {
4.     angle   = new float3(0, 1.5708f, 0),
5.     vertices = vertices,
6.     offset   = new float3(0, 5, 0)
7. };
8.  
9. test.Schedule().Complete();
10. Debug.Log(vertices[0]);
11. vertices.Dispose();
12.  

Code (CSharp):

1. [BurstCompile]
2.     public struct SomeBurstedJob : IJob
3.     {
4.         public NativeList<float3> vertices;
5.         public float3             angle;
6.         public float3             offset;
7.  
8.         public void Execute()
9.         {          
10.             float3 vertex = math.rotate(quaternion.Euler(angle), new float3(0, 0, 10)) + offset;
11.  
12.             vertices.Add(vertex);
13.         }
14.     }
15.  

It's also crashes. Again, only with Burst.

 

Well, because of the help from @eizenhorn (Thank you!!) I could continue investigation with my issue and after a series of tests I am inclined to believe now, that most of the problems since the beggining here somehow arose because of Unity.Mathematics usage.
If I'm right, there is even no need to have use the whole package for crash, like I did above.
For example here I made for loop based on the value obtained from "NativeArray<int2>"(I actually wanted to use int2 from the beginning).

Code (CSharp):

1. [BurstCompile]
2.     private struct SomeBurstedJob : IJob
3.     {
4.         public NativeList<Vector3> vertices;
5.         public NativeArray<int2> indexMax;
6.         public Vector3             vector;
7.         public Vector3             offset;
8.         public void Execute()
9.         {
10.             Quaternion rotation = new Quaternion();
11.             rotation.eulerAngles = vector;
12.  
13.             int tempIntForExample = indexMax[0].y;
14.             for (int i = 0; i < tempIntForExample; i++)
15.             {
16.                 Vector3 vertex = (rotation * new Vector3(0, 0, 10)) + new Vector3(0, 5, 0);
17.                 vertices.Add(vertex);
18.             }
19.         }
20.     }

And that's crash. At least for me. Am I suppose to "Report A Bug" it then?
Also, "indexMax[0].y" here is equal to one hundred, and when I change it instead of "NativeArray<int2>" to just "NativeArray<int>" - it's not crashing. So that's why I think this is it.
And also, I am using last available version of Mathematics(1.0.0 preview 1).

 

What happens if you pull out the int2 and then access the y component? Does it still crash then?

 

Pull out of what?
Mm, if y component not readed inside of the job and you just only read it after the job when it's Complete on main thread - it's fine. Even if int2 was modyfied to new value when inside of bursted job.

So it's look's like write something to such NativeContainer it is okay here.
But if I write from one "NativeArray<int2>" to another "NativeArray<int2>" with "=" it's also crash.
I guess because it's acually reading from second NativeContainer.

* If I do modify "NativeArray<int2>" with some "new Int2(0, 100)" in the job, but then read it inside the same job for some cause, whatsoever - it's still crash.
* If it's same code like above in the post, but with other type temp value used after or if without some temp value at all - it's also crash. So it's acual issue with reading when, as I believe.
* And again if it's not a "NativeContainer" and just int2 or if it's "NativeContainer<int>" - then it's fine to read&write or do something inside of bursted job with it.

 

Show please your manifest.json inside Package folder

 

Here.

Spoiler: manifest.json

Code (CSharp):

1. {
2.   "dependencies": {
3.     "com.unity.ads": "2.0.8",
4.     "com.unity.analytics": "3.2.2",
5.     "com.unity.burst": "1.0.0-preview.6",
6.     "com.unity.collab-proxy": "1.2.15",
7.     "com.unity.collections": "0.0.9-preview.12",
8.     "com.unity.mathematics": "1.0.0-preview.1",
9.     "com.unity.package-manager-ui": "2.0.7",
10.     "com.unity.postprocessing": "2.1.4",
11.     "com.unity.purchasing": "2.0.3",
12.     "com.unity.render-pipelines.high-definition": "4.10.0-preview",
13.     "com.unity.shadergraph": "4.10.0-preview",
14.     "com.unity.textmeshpro": "1.3.0",
15.     "com.unity.visualeffectgraph": "4.10.0-preview",
16.     "com.unity.modules.ai": "1.0.0",
17.     "com.unity.modules.animation": "1.0.0",
18.     "com.unity.modules.assetbundle": "1.0.0",
19.     "com.unity.modules.audio": "1.0.0",
20.     "com.unity.modules.cloth": "1.0.0",
21.     "com.unity.modules.director": "1.0.0",
22.     "com.unity.modules.imageconversion": "1.0.0",
23.     "com.unity.modules.imgui": "1.0.0",
24.     "com.unity.modules.jsonserialize": "1.0.0",
25.     "com.unity.modules.particlesystem": "1.0.0",
26.     "com.unity.modules.physics": "1.0.0",
27.     "com.unity.modules.physics2d": "1.0.0",
28.     "com.unity.modules.screencapture": "1.0.0",
29.     "com.unity.modules.terrain": "1.0.0",
30.     "com.unity.modules.terrainphysics": "1.0.0",
31.     "com.unity.modules.tilemap": "1.0.0",
32.     "com.unity.modules.ui": "1.0.0",
33.     "com.unity.modules.uielements": "1.0.0",
34.     "com.unity.modules.umbra": "1.0.0",
35.     "com.unity.modules.unityanalytics": "1.0.0",
36.     "com.unity.modules.unitywebrequest": "1.0.0",
37.     "com.unity.modules.unitywebrequestassetbundle": "1.0.0",
38.     "com.unity.modules.unitywebrequestaudio": "1.0.0",
39.     "com.unity.modules.unitywebrequesttexture": "1.0.0",
40.     "com.unity.modules.unitywebrequestwww": "1.0.0",
41.     "com.unity.modules.vehicles": "1.0.0",
42.     "com.unity.modules.video": "1.0.0",
43.     "com.unity.modules.vr": "1.0.0",
44.     "com.unity.modules.wind": "1.0.0",
45.     "com.unity.modules.xr": "1.0.0"
46.   }
47. }
48.  

 

Are you still using Unity 2018.3 by any chance? (All my 2019 project have

com.unity.package-manager-ui

higher than 2.1.0)
And I dont see Entities package. It possible that something go wrong internally when Burst not work with Entity.

 

Burst not related on Entities package.
@SiriusRU
But I too recommend use 2019 for latest Burst.

 

As I said above, yes, I am using Unity 2018.3.9f1. And this is true that the project does not contain an Entity package, although it's use is further were implied for creatures, NPCs, and some other things. But I added this package to the project, like - you never know, but no, in itself it did not change anything, so @eizenhorn is right, so it's not connected with issue here.

Well, I have already tried to port project to 2019 version, briefly and without success, and now I should try again because
I have made a separate empty project on the latest version of Unity 2019 with all the necessary packages - very glad to note that mentioned issue not occure there with all code samples from above. Definitely should have checked this like that earlier.

Thank you very much for your help - although this does not solve the problem for 2018 version, which is sad, but it might actually solve issue at least for me, especially I was planning to move in for 2019 sooner or later anyway.

It is lovely to hear that. Thank you!

 

@xoofx sure. This link here?

I also were wrong, trouble actually occure in 2019 version too -_-"
It's Unity 2019.2.0a9 and burst 1.0.0 preview.6.
Due to the fact that crash mostly does not happen immediately at first schedule - I thought that everything is okay - it's like working at first and after scheduling it's 2-10 times makes Unity instant crash and I just have to restart editor. That's exactly what happening in repro for me. Wonder what could possibly be the reason.

If I do not use Mathematics and rely only on Vector3, Mathf, Quaternion, etc. - everything works stable. In fact, I am currently use a temporary solution that does not use Mathematics and it never crashes, although it uses Job with Burst almost constantly.

 

Hm. If so, could you please tell - would it be fixable then?
As I can see my CPU supports SSE4a, but not SSE4.1 or SSE4.2. Does it mean, that I am unable to fully use BurstCompiler?

Spoiler: CPU-Z

Spoiler: CoreInfo

Coreinfo v3.31 - Dump information on system CPU and memory topology
Copyright (C) 2008-2014 Mark Russinovich
Sysinternals - www.sysinternals.com

AMD Athlon(tm) II X2 280 Processor
AMD64 Family 16 Model 6 Stepping 3, AuthenticAMD
Microcode signature: 010000C8
HTT * Multicore
HYPERVISOR - Hypervisor is present
VMX - Supports Intel hardware-assisted virtualization
SVM * Supports AMD hardware-assisted virtualization
X64 * Supports 64-bit mode

SMX - Supports Intel trusted execution
SKINIT * Supports AMD SKINIT

NX * Supports no-execute page protection
SMEP - Supports Supervisor Mode Execution Prevention
SMAP - Supports Supervisor Mode Access Prevention
PAGE1GB * Supports 1 GB large pages
PAE * Supports > 32-bit physical addresses
PAT * Supports Page Attribute Table
PSE * Supports 4 MB pages
PSE36 * Supports > 32-bit address 4 MB pages
PGE * Supports global bit in page tables
SS - Supports bus snooping for cache operations
VME * Supports Virtual-8086 mode
RDWRFSGSBASE - Supports direct GS/FS base access

FPU * Implements i387 floating point instructions
MMX * Supports MMX instruction set
MMXEXT * Implements AMD MMX extensions
3DNOW * Supports 3DNow! instructions
3DNOWEXT * Supports 3DNow! extension instructions
SSE * Supports Streaming SIMD Extensions
SSE2 * Supports Streaming SIMD Extensions 2
SSE3 * Supports Streaming SIMD Extensions 3
SSSE3 - Supports Supplemental SIMD Extensions 3
SSE4a * Supports Streaming SIMDR Extensions 4a
SSE4.1 - Supports Streaming SIMD Extensions 4.1
SSE4.2 - Supports Streaming SIMD Extensions 4.2

AES - Supports AES extensions
AVX - Supports AVX intruction extensions
FMA - Supports FMA extensions using YMM state
MSR * Implements RDMSR/WRMSR instructions
MTRR * Supports Memory Type Range Registers
XSAVE - Supports XSAVE/XRSTOR instructions
OSXSAVE - Supports XSETBV/XGETBV instructions
RDRAND - Supports RDRAND instruction
RDSEED - Supports RDSEED instruction

CMOV * Supports CMOVcc instruction
CLFSH * Supports CLFLUSH instruction
CX8 * Supports compare and exchange 8-byte instructions
CX16 * Supports CMPXCHG16B instruction
BMI1 - Supports bit manipulation extensions 1
BMI2 - Supports bit manipulation extensions 2
ADX - Supports ADCX/ADOX instructions
DCA - Supports prefetch from memory-mapped device
F16C - Supports half-precision instruction
FXSR * Supports FXSAVE/FXSTOR instructions
FFXSR * Supports optimized FXSAVE/FSRSTOR instruction
MONITOR * Supports MONITOR and MWAIT instructions
MOVBE - Supports MOVBE instruction
ERMSB - Supports Enhanced REP MOVSB/STOSB
PCLMULDQ - Supports PCLMULDQ instruction
POPCNT * Supports POPCNT instruction
LZCNT * Supports LZCNT instruction
SEP * Supports fast system call instructions
LAHF-SAHF * Supports LAHF/SAHF instructions in 64-bit mode
HLE - Supports Hardware Lock Elision instructions
RTM - Supports Restricted Transactional Memory instructions

DE * Supports I/O breakpoints including CR4.DE
DTES64 - Can write history of 64-bit branch addresses
DS - Implements memory-resident debug buffer
DS-CPL - Supports Debug Store feature with CPL
PCID - Supports PCIDs and settable CR4.PCIDE
INVPCID - Supports INVPCID instruction
PDCM - Supports Performance Capabilities MSR
RDTSCP * Supports RDTSCP instruction
TSC * Supports RDTSC instruction
TSC-DEADLINE - Local APIC supports one-shot deadline timer
TSC-INVARIANT * TSC runs at constant rate
xTPR - Supports disabling task priority messages

EIST - Supports Enhanced Intel Speedstep
ACPI - Implements MSR for power management
TM - Implements thermal monitor circuitry
TM2 - Implements Thermal Monitor 2 control
APIC * Implements software-accessible local APIC
x2APIC - Supports x2APIC

CNXT-ID - L1 data cache mode adaptive or BIOS

MCE * Supports Machine Check, INT18 and CR4.MCE
MCA * Implements Machine Check Architecture
PBE - Supports use of FERR#/PBE# pin

PSN - Implements 96-bit processor serial number

PREFETCHW * Supports PREFETCHW instruction

Maximum implemented CPUID leaves: 00000005 (Basic), 8000001B (Extended).

Up to this point, I thought my processor was quite suitable, I wouldn't say there were any problems.

 

Thank you for working on this. Well, I used the project attached to the report in Unity 2019.0.a9 and updated the packages. Burst kind of works, but for some reason, Jobs started work only on main thread. That's quite weird.
But at least there is no crashes.

Spoiler: Profiler screenshots

See for "TestJob".
I also increased the number of "for" iteration inside to make it litle bit longer and more obvious.


With Burst "Enable Compilation" disabled.

It would be probably right to mention that I'm going to change my CPU to another one with SSE4.1 + SSE4.2 support tomorrow, so I'm also not sure if I will be able to check Burst workability in same manner later.