Hi all
I have a small conflict with the pid_hashfn, I don't unsertand because
this function not use a simple MODULO for create a index in a table
With the act function , use shift, XOR and & bits operation for lookup the
unique ( with 32 maxium colision for bucket) index in a table, but with a
simple module of PIDHASHSZ -1 is the same operation.
This is the actual :
#define pid_hashfn(x) ((((x) >>8)^(x))&(PIDHASH_SZ-1))
And with calculate de modulo :
#define pid_hashfn(x) ((x)&(PIDHASH_SZ-1))
With this small code i have calculated de collisions in a large of table
memset(&table,0,PIDHASH_SZ*sizeof(int));
for(k=0;k<32768;k++)
table[pid_hashfn(k)]++;
for(k=0;k<PIDHASH_SZ;k++)
printf("%d (%d)\n",k,table[k]);
--
Pau Freixes
www.lana2.com/pfreixes
$GNU/Linux user$
--
Kernelnewbies: Help each other learn about the Linux kernel.
Archive: http://mail.nl.linux.org/kernelnewbies/
FAQ: http://kernelnewbies.org/faq/
