[erlang-questions] Memory usage

[Francesca Gangemi]

Hi,

we notice that nodes crash during a load test because they cannot 
allocate more memory.
The slogan from the crash dump says
"eheap_alloc: Cannot allocate 3328160 bytes of memory (of type old_heap")."

Memory information reports the following values
total              2468460696
processes     2060871072
processes_used     2060858920
system              407589624

If then I look at the process information and I add up the Stack+heap 
values for all the processes I get 243183460 bytes. This number is quite 
less than the processes_used one.
I wonder if something else is added up to the process_used memory value.

We run the test using R11B-3 and R12B-4.
There are 6000 processes running under a supervisor. They generate xml 
requests and parse xml responses. The XML structure is quite complex and 
its size is up to 80KB.

The following lines report information about allocated areas

sys_misc     3422757     
static     14417920     
atom_space     163860    162413
atom_table     91901     
module_table     5768     
export_table     48008     
register_table     852     
fun_table     3250     
module_refs     4096     
loaded_code     4553244     
dist_table     555     
node_table     299     
bits_bufs_size     0     
bif_timer     40604     
link_lh     0     
proc     3995708    3988028
atom_entry     316564    316276
export_entry     312364    312172
module_entry     12088    11888
reg_proc     6320    6104
monitor_sh     253288    252248
nlink_sh     362060    358844
proc_list     28    28
fun_entry     60724    60220
db_tab     12848    10416
driver_event_data_state     28    28
driver_select_data_state     1000    328


Kind regards
Francesca