mersenneforum.org  

Go Back   mersenneforum.org > Great Internet Mersenne Prime Search > Hardware > GPU Computing

Reply
 
Thread Tools
Old 2015-01-02, 22:49   #1288
kracker
 
kracker's Avatar
 
"Mr. Meeseeks"
Jan 2012
California, USA

32×241 Posts
Default

Quote:
Originally Posted by Bdot View Post
Hmm. Weird. Now it is at 424 GHz ... I'll monitor it. Looks like something ran in the background ...
Wow... this is weird. I had reverted to a older driver(14.3) and it still gave me errors when I ran -st2 just now. Going to do a little investigating...
kracker is offline   Reply With Quote
Old 2015-01-05, 00:55   #1289
kracker
 
kracker's Avatar
 
"Mr. Meeseeks"
Jan 2012
California, USA

32·241 Posts
Default

Hmm, I don't know what's up. -st2 with GCN2 works, and mfakto 0.14 works too...
kracker is offline   Reply With Quote
Old 2015-01-12, 15:57   #1290
Bdot
 
Bdot's Avatar
 
Nov 2010
Germany

11258 Posts
Default

Quote:
Originally Posted by kracker View Post
Hmm, I don't know what's up. -st2 with GCN2 works, and mfakto 0.14 works too...
Now my GPU slowed down again. Seems to be the GPU memory access that almost blocks it. I still blame the driver.

Anyway, I now reproduced the error (I just needed to set GPUType=GCN ). I did not yet check why 0.14 does not show this, but the reason is that I missed a part in my error estimation. The 15-82, 15-83 and 15-88 bit kernels can have a higher error than I expected - so they cannot reliably do the last bitlevel they're enabled for. In other words, if you've done TF tests beyond 81 bits using a GCN GPU, there's a small chance of missed factors. Not sure how small, but most of the selftests do succeed. I'll try to find out about 0.14 tonight.

To fix it, I can either reduce the kernels' bitlevel, or add code to reduce the error, which will slow it down a bit. I have not yet decided.
Bdot is offline   Reply With Quote
Old 2015-01-12, 23:22   #1291
Bdot
 
Bdot's Avatar
 
Nov 2010
Germany

3·199 Posts
Exclamation Mfakto 0.14 bug warning for 81-82, 82-83 and 87-88 bit tests

mfakto version 0.14 did not have these errors because the failing tests were part of another 2300 tests that I only added for 0.15. I built a version of 0.14 with just these tests added, and they are failing too.

This means that these tests were unreliable:
  • run 81-82, 82-83 or 87-88 bits on any GCN GPU (other GPUs would select a different kernel)
  • out of 262 test cases in these 3 ranges, 9 are failing (~3.5%). Due to the small number of tests, the error percentage is rather inexact.
Please do not use mfakto 0.14 for tests beyond 80 bits on GCN. I will reduce the bitlevels of these kernels to a safe level for 0.15 and add another kernel that has the additional code to safely run to 88 bits.

I'm sorry.
Bdot is offline   Reply With Quote
Old 2015-01-13, 05:45   #1292
LaurV
Romulan Interpreter
 
LaurV's Avatar
 
Jun 2011
Thailand

25×5×59 Posts
Default

Very good job Bdot!
(it does not affect me, due to the speed penalty at higher bitlevels, I used my 7970 higher than 72 bits only very seldom, but the effort to fix the tool and the recognizing of own slips, this scales very high in my book!)
LaurV is offline   Reply With Quote
Old 2015-03-20, 19:38   #1293
tului
 
Jan 2013

22×17 Posts
Default

My Beema(A8-6410) takes a crap trying to run mfakto built from the github source. Is there a linux binary available or any tests and log files you'd like me to run on my builds?
tului is offline   Reply With Quote
Old 2015-03-25, 00:23   #1294
Bdot
 
Bdot's Avatar
 
Nov 2010
Germany

3×199 Posts
Default

Quote:
Originally Posted by tului View Post
My Beema(A8-6410) takes a crap trying to run mfakto built from the github source. Is there a linux binary available or any tests and log files you'd like me to run on my builds?
Sorry to say, but I currently have no time to really help here, especially when the error description is as vage as "takes a crap" (I could not find this string in the source code).
Bdot is offline   Reply With Quote
Old 2015-03-25, 04:13   #1295
tului
 
Jan 2013

22·17 Posts
Default

I was asking if there is any -st -st2 type stuff you'd like me to log and report back.Of course I can give you the exact error message as well. Wasn't thinking about that when I posted.
tului is offline   Reply With Quote
Old 2015-03-25, 18:33   #1296
TheMawn
 
TheMawn's Avatar
 
May 2013
East. Always East.

11×157 Posts
Default

Quote:
Originally Posted by Bdot View Post
"takes a crap" (I could not find this string in the source code).
TheMawn is offline   Reply With Quote
Old 2015-03-26, 11:44   #1297
tului
 
Jan 2013

22·17 Posts
Default

Quote:
Originally Posted by TheMawn View Post
We could always do a git merge :-P
tului is offline   Reply With Quote
Old 2015-05-02, 05:32   #1298
frmky
 
frmky's Avatar
 
Jul 2003
So Cal

23·32·29 Posts
Default

I tried playing with this a bit today, but I'm getting an error:

Code:
mfakto 0.15pre5 (64bit build)


Runtime options
  Inifile                   mfakto.ini
  Verbosity                 1
  SieveOnGPU                yes
  MoreClasses               yes
  GPUSievePrimes            81157
  GPUSieveProcessSize       24Ki bits
  GPUSieveSize              96Mi bits
  FlushInterval             0
  WorkFile                  worktodo.txt
  ResultsFile               results.txt
  Checkpoints               enabled
  CheckpointDelay           300s
  Stages                    enabled
  StopAfterFactor           class
  PrintMode                 compact
  V5UserID                  none
  ComputerID                none
  TimeStampInResults        yes
  VectorSize                2
  GPUType                   AUTO
  SmallExp                  no
  UseBinfile                mfakto_Kernels.elf
Compiletime options
  DEBUG_FACTOR_FIRST        enabled (DEBUG option)

Select device - Get device info:

OpenCL device info
  name                      Hawaii (Advanced Micro Devices, Inc.)
  device (driver) version   OpenCL 2.0 AMD-APP (1642.5) (1642.5 (VM))
  maximum threads per block 256
  maximum threads per grid  16777216
  number of multiprocessors 44 (2816 compute elements)
  clock rate                1000MHz

Automatic parameters
  threads per grid          0
  optimizing kernels for    GCN3

Loading binary kernel file mfakto_Kernels.elf
Compiling kernels.
Started a simple selftest ...
ERROR: selftest failed for M1031831 (cl_barrett15_69_gs)
  no factor found
Selftest statistics                                    
  number of tests           30
  successful tests          29
  no factor found           1

selftest FAILED!
Version 0.14 passes both -st and -st2. Is this the error mentioned earlier?
frmky is offline   Reply With Quote
Reply

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
gpuOwL: an OpenCL program for Mersenne primality testing preda GpuOwl 2706 2021-05-02 21:40
mfaktc: a CUDA program for Mersenne prefactoring TheJudger GPU Computing 3493 2021-04-24 17:09
LL with OpenCL msft GPU Computing 433 2019-06-23 21:11
OpenCL for FPGAs TObject GPU Computing 2 2013-10-12 21:09
Program to TF Mersenne numbers with more than 1 sextillion digits? Stargate38 Factoring 24 2011-11-03 00:34

All times are UTC. The time now is 14:32.

Fri May 7 14:32:04 UTC 2021 up 29 days, 9:12, 0 users, load averages: 5.70, 4.91, 4.00

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.

This forum has received and complied with 0 (zero) government requests for information.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation.
A copy of the license is included in the FAQ.