[phobos] [D-Programming-Language/phobos] 3cf671: Add std.parallelism.

Wed Apr 27 05:40:53 PDT 2011

On 4/27/2011 12:10 AM, Brad Roberts wrote:
> It's a dual core amd:
>
> vendor_id       : AuthenticAMD
> cpu family      : 15
> model           : 75
> model name      : AMD Athlon(tm) 64 X2 Dual Core Processor 3800+
> stepping        : 2
> cpu MHz         : 1000.000
> cache size      : 512 KB
> flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht
> syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow rep_good extd_apicid pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy
>
> Actually, showing up on one box but not another is strong evidence of a concurrency bug in my experience.  Different
> cpu's at different speeds, with different speed memory and other side components change timings enough to expose bugs
> that otherwise haven't occurred elsewhere.

Agreed, but the fact that I've used this thing on a whole bunch of 
different machines (including one very similar to the one above; my 
machine has an almost identical spec) and it passed Jinx is strong 
evidence against one.  I don't know how I'm going to debug this given it 
only occurs on setups that I don't have access to.

> On 4/26/2011 8:44 PM, David Simcha wrote:
>> What about the Linux 64 machine?  I'm getting some weird segfaults in std.parallelism that I can't reproduce on my Linux
>> 64 VM.  I'm currently running the std.parallelism unittests in a loop and they're passing every time.  Furthermore, I've
>> been using std.parallelism for real work on Linux 64 since DMD was capable of producing 64-bit binaries and it's worked
>> fine.  It also passed a Jinx test a few weeks back.  (Jinx is software that's designed to make buggy multithreaded
>> programs fail by fiddling with timings.  Bartosz Milewski tested std.parallelism with it after seeing my blog post.  The
>> point is that this is evidence against the issue being a latent concurrency bug.)  Therefore, I'm thinking something
>> very weird is going on with auto tester.
>>
>> Also, I noticed it's segfaulting on FreeBSD, too.  I'm installing a FreeBSD VM right now to look into this.
>>
>> On 4/26/2011 9:38 PM, Brad Roberts wrote:
>>> Good point.. I'll make a note to myself to add system definitions for
>>> those boxes somewhere obvious since that's important for some things.  The
>>> freebsd box is an ancient pos, but it works:
>>>
>>> CPU: Intel(R) Pentium(R) 4 CPU 3.00GHz (2992.52-MHz 686-class CPU)
>>>     Origin = "GenuineIntel"  Id = 0xf41  Family = f  Model = 4  Stepping = 1
>>>
>>> Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
>>>
>>>     Features2=0x441d<SSE3,DTES64,MON,DS_CPL,CNXT-ID,xTPR>
>>>     TSC: P-state invariant
>>> real memory  = 2147483648 (2048 MB)
>>> avail memory = 2091065344 (1994 MB)
>>> ACPI APIC Table:<A M I  OEMAPIC>
>>> FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
>>> FreeBSD/SMP: 1 package(s) x 1 core(s) x 2 HTT threads
>>>    cpu0 (BSP): APIC ID:  0
>>>    cpu1 (AP/HT): APIC ID:  1
>>>
>>>
>>>
>>> On Tue, 26 Apr 2011, David Simcha wrote:
>>>
>>>> Date: Tue, 26 Apr 2011 21:02:07 -0400
>>>> From: David Simcha<dsimcha at gmail.com>
>>>> Reply-To: Discuss the phobos library for D<phobos at puremagic.com>
>>>> To: Discuss the phobos library for D<phobos at puremagic.com>
>>>> Subject: Re: [phobos] [D-Programming-Language/phobos] 3cf671: Add
>>>>       std.parallelism.
>>>>
>>>> I actually realized that FreeBSD matters by looking at the auto tester to make
>>>> sure the checkin wasn't breaking anything on OSX, which I also don't have
>>>> access to.  I have a static assert that will probably fail (fixing it right
>>>> now since it's trivial).  The other issue is that FreeBSD appears broken for
>>>> unrelated reasons right now.  I just pushed a fix based on reading some
>>>> documentation about FreeBSD, but I have no idea whether it's right or not
>>>> because I don't have a FreeBSD box to test it on.  Also, the functionality is
>>>> hard to automatically test because you need to know how many cores the box
>>>> you're running on actually has.
>>>>
>>>> On 4/26/2011 8:45 PM, Brad Roberts wrote:
>>>>> Assuming you have a good unit test for it, just check the auto tester...
>>>>> Yes, freebsd/32 is supported for d2.
>>>>>
>>>>> On Tue, 26 Apr 2011, David Simcha wrote:
>>>>>
>>>>>> Just realized, are we supporting D2 on FreeBSD yet?  If so, I need to fix
>>>>>> std.parallelism to detect the number of CPUs on it.  I think this is the
>>>>>> same
>>>>>> as on OSX, though.  (I used sysctlbyname on OSX.  Someone please confirm
>>>>>> this
>>>>>> is right on BSD.)
>>>>>>
>>>>>> On 4/26/2011 8:06 PM, noreply at github.com wrote:
>>>>>>> Branch: refs/heads/master
>>>>>>> Home:   https://github.com/D-Programming-Language/phobos
>>>>>>>
>>>>>>> Commit: 3cf67160b82d87d8de0bc7564aa1474149a92349
>>>>>>>         https://github.com/D-Programming-Language/phobos/commit/3cf67160b82d87d8de0bc7564aa1474149a92349
>>>>>>> Author: dsimcha<dsimcha at gmail.com>
>>>>>>> Date:   2011-04-26 (Tue, 26 Apr 2011)
>>>>>>>
>>>>>>> Changed paths:
>>>>>>>       M changelog.dd
>>>>>>>       M posix.mak
>>>>>>>       A std/parallelism.d
>>>>>>>       M unittest.d
>>>>>>>       M win32.mak
>>>>>>>
>>>>>>> Log Message:
>>>>>>> -----------
>>>>>>> Add std.parallelism.
>>>>>>>
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