Difference between revisions of "Main Page/DAT"

Revision as of 14:41, 13 June 2012

 ldim: dimension

 lxi: the degree of polynomials
 lx1: the number of grid points on the face 
 ly1=lx1; lz1=lx1

 lelt: the maximun number of element per core

 lp : the maximum number of cores

We'll have to use (E,lelt,lx1,lp), to represent size of prob, instead of c3d.rea.

E=total element numbers, lelt=element # per core,
lx1= grid points in one direction, lp= # of cores.

I had many different rea with c3d_6 (E=136K), c3d_7(E=273K), etc..

Even for a fixed num of element with c3d_7 (E=273K), men usage is different for different # of cores (lp=32k, 65k, 131k).

made huge change in the code for 2 times

reduction in mem usage to go further up from 1.1 billion to 2.2 billion cases.

 from (E=273, lx1=16, lp= 131k): limit in the past  ---> (E=546k, lx1=16, lp=131k)

(E=999k, lx1=16, lp=131k) was 500M. So I couldn't do on BGP. But is be ok on XK6, even with lp=262k.

In there, if we assume "nc" is approximately same as the total grids "n". we have the following:

 For the header:
 (1) coordinate => 3 columns * 4 bytes
 (2) cell data  => 9 columns * 4 bytes
 (3) cell type  => 1 columns * 4 bytes

 For the 8 fields:
     3 columns * 4 bytes

So, we have 275M*(8 fields *3*4)+ 275M*(3+9+1)*4 = 40 GB

Or, neglecting the cel type, we get 275M(8*3*4+12*4)=39GB

The problem size on 32k cores was npt= 546000*16*16*16 = E*lx1*lx1*lx1 (where lx1=lxi+1). i.e., npt=2,236,416,000 = 2.2 billion grids

The output size with 4 fields will be: 2236416000*(4*3*4)+2236416000*(1+9+3)*4 = 223,641,600,000 (223GB)

Memory required is 420M .

TODO: make sure thread joined at last step; make sure buffer size is optimized according to the formula given above;

@@ Line 20: / Line 20: @@
 Even for a fixed num of element with c3d_7 (E=273K), men usage is different for
-different # of cores (lp=32k, 65k, 131k).  So... sorry I wouldn't know which
+different # of cores (lp=32k, 65k, 131k).
-case if it's just c3d...
-By the way, please remember I made huge change in the code so far for 2 times
+ made huge change in the code for 2 times
 reduction in mem usage to go further up from 1.1 billion to 2.2 billion cases.
@@ Line 30: / Line 29: @@
 (E=999k, lx1=16, lp=131k) was 500M. So I couldn't do on BGP. But is be ok on XK6,
 even with lp=262k.
-If you still keep the old version old version of the code: you can compile and
-see what men usage was. From example below, always the fourth one (92352484) will
-be the mem usage.
@@ Line 48: / Line 42: @@
 columns * 4 bytes
-So, we have 275M*(8 fields *3*4)+ 275M*(3+9+1)*4 = 40 GB ?
+So, we have 275M*(8 fields *3*4)+ 275M*(3+9+1)*4 = 40 GB
-Or, neglecting the cel type, we get 275M(8*3*4+12*4)=39GB ?
+Or, neglecting the cel type, we get 275M(8*3*4+12*4)=39GB
@@ Line 64: / Line 53: @@
 2236416000*(4*3*4)+2236416000*(1+9+3)*4 = 223,641,600,000 (223GB)
-Memory required is 420M (I wouldn't know how to get breakdown of memory for computation and I/O)
+Memory required is 420M .
-But let me know if anyway that we can get the info -- we can work on it.