Largest matrix dimension for DSYEV?

General CULA Dense (LAPACK & BLAS) support and troubleshooting. Use this forum if you are having a general problem or have encountered a bug.

Largest matrix dimension for DSYEV?

Postby ningfengh » Tue Jun 11, 2013 10:13 am

Currently I ran a benchmark (using the one in the example folder) of the subroutine DSYEV and get the following result.

Initializing CULA...
Initializing MKL...

Benchmarking the following functions:
-------------------------------------
DSYEV
-------------------------------------


-- DSYEV Benchmark --

Size CULA (s) MKL (s) Speedup
------ ---------- ---------- ---------
1024 0.29 0.26 0.8799
2048 0.65 0.45 0.6813
3072 1.55 0.89 0.5721
4096 2.85 3.01 1.0563
5120 4.52 6.47 1.4294
6144 6.84 10.23 1.4943
7168 9.59 14.72 1.5347
8192 13.14 21.90 1.6667
9216 17.24 27.78 1.6116
10240 22.08 36.65 1.6601
11264 27.74 46.85 1.6890
12288 33.88 58.92 1.7391
13312 41.21 73.21 1.7765
14336 49.48 90.24 1.8239
15360 59.19 110.20 1.8618
16384 69.52 156.04 2.2445
17408 80.26 155.48 1.9372
18432 92.58 179.42 1.9381
19456 107.06 206.71 1.9309
20480 121.99 234.07 1.9188
21504 138.50 271.49 1.9602
22528 155.97 308.07 1.9752
23552 175.62 352.68 2.0082
24576


The first thing I saw is that the speedup is not very spectacular. Is it something I would expect from CULA? And then the job crashes at 24576 without any error output. Is this the largest matrix can be managed in our graphical card?

The following are the specs of the system,

dual 8-core 2.4 gigahertz Intel E5-2665 processors
64 gigabytes of memory
two NVIDIA K20 Kepler GPU accelerators

CULA Dense R17
MKL 12.1.1
ningfengh
 
Posts: 2
Joined: Wed Jun 05, 2013 10:27 am

Re: Largest matrix dimension for DSYEV?

Postby john » Tue Jun 11, 2013 1:39 pm

CULA requires that all data fit on the GPU simultaneously, so when you hit the limit of the K20, it will be unable to go any further. Note that CULA uses only one GPU for this but MKL uses both processors, so you're comparing $3000 of processors to $3000 of GPUs - 2x is pretty decent, given this setup. (SYEV is algorithmically also not our highest performing routine)
john
Administrator
 
Posts: 587
Joined: Thu Jul 23, 2009 2:31 pm

Re: Largest matrix dimension for DSYEV?

Postby ningfengh » Tue Jun 11, 2013 4:24 pm

john wrote:CULA requires that all data fit on the GPU simultaneously, so when you hit the limit of the K20, it will be unable to go any further. Note that CULA uses only one GPU for this but MKL uses both processors, so you're comparing $3000 of processors to $3000 of GPUs - 2x is pretty decent, given this setup. (SYEV is algorithmically also not our highest performing routine)


Thanks John.

Where can I find the memory usage as a function of dimensions of matrices for different routines ? I think that will be a quite important reference for me.

Another question, if I use pCULA routine and use two K20, can I do a larger matrix ?
ningfengh
 
Posts: 2
Joined: Wed Jun 05, 2013 10:27 am

Re: Largest matrix dimension for DSYEV?

Postby john » Wed Jun 12, 2013 5:35 am

There are no eigensolvers in pCULA, unfortunately.

Memory usage for most CULA routines is only a few megabytes besides what you put into the routine. In the case of SYEV, it's just the size of the matrices.
john
Administrator
 
Posts: 587
Joined: Thu Jul 23, 2009 2:31 pm


Return to CULA Dense Support

Who is online

Users browsing this forum: No registered users and 1 guest

cron