Giving more CPU time to a swapping process?

[Karl Ma]

Hi,

I have a python program in freebsd, doing a heavey indexing job involving a
mega size array.

The process is so memory-hungry that it starts swap after the physical RAM
max out. (To be exact, I've lowered the per-process limitation to make this
possible).

However, when I use top to monitor the status, the STATE of the process
started to stay as "swread" for most of the time (instead of RUN before
using swap) and its priority has dropped to -20; and the corresponding WCPU
drops to around 1% only. And the CPU consumption time in total (for the
whole job) would only increase a minute or two even the process has been
running for more than a few hours.
In Windows XP, which has less per-task resource restriction (I guess?), I
did successfully complete the task on the same hardware machine; although it
takes more than 30 mins.

How can I push up the priority of the whole paging task? How can I
allocate more CPU attention to this process? I've tried using "nice"
but it does not help.

Please refer to the below top's snapshots at different times. (A) is earlier
than (B), and so on.

Thanks for your help in advance.


= (A) =
last pid:   766;  load averages:  0.66,  0.21,  0.11    up 0+00:19:54
23:23:04
63 processes:  2 running, 61 sleeping
CPU states: 96.6% user,  0.0% nice,  3.4% system,  0.0% interrupt,  0.0%idle
Mem: 341M Active, 35M Inact, 98M Wired, 704K Cache, 91M Buf, 522M Free
Swap: 998M Total, 998M Free

PID USERNAME  THR PRI NICE   SIZE    RES STATE    TIME   WCPU COMMAND
751 root        1 118    0   245M   244M RUN      0:59 96.57% python

= (B) =
last pid:   792;  load averages:  1.02,  0.70,  0.36    up 0+00:24:20
23:27:30
62 processes:  2 running, 60 sleeping
CPU states: 92.5% user,  0.0% nice,  6.0% system,  1.5% interrupt,  0.0%idle
Mem: 766M Active, 67M Inact, 115M Wired, 45M Cache, 109M Buf, 3636K Free
Swap: 998M Total, 37M Used, 962M Free, 3% Inuse, 17M Out

PID USERNAME  THR PRI NICE   SIZE    RES STATE    TIME   WCPU COMMAND
751 root        1 128    0   744M   743M RUN      5:14 94.63% python

= (C) =
last pid:   792;  load averages:  1.06,  0.81,  0.43    up 0+00:25:54
23:29:04
62 processes:  2 running, 60 sleeping
CPU states: 95.5% user,  0.0% nice,  4.1% system,  0.4% interrupt,  0.0%idle
Mem: 849M Active, 2868K Inact, 115M Wired, 28M Cache, 109M Buf, 1656K Free
Swap: 998M Total, 95M Used, 903M Free, 9% Inuse, 236K Out

PID USERNAME  THR PRI NICE   SIZE    RES STATE    TIME   WCPU COMMAND
751 root        1 128    0   848M   841M RUN      6:42 91.46% python

= (D) =
last pid:   792;  load averages:  1.15,  0.87,  0.47    up 0+00:26:36
23:29:46
62 processes:  1 running, 61 sleeping
CPU states: 28.6% user,  0.0% nice, 18.8% system,  1.5% interrupt, 51.1%idle
Mem: 843M Active, 5380K Inact, 116M Wired, 31M Cache, 109M Buf, 1656K Free
Swap: 998M Total, 142M Used, 856M Free, 14% Inuse, 932K In, 56M Out

PID USERNAME  THR PRI NICE   SIZE    RES STATE    TIME   WCPU COMMAND
751 root        1 -20    0   878M   841M swread   7:14 79.05% python

= (E) =
last pid:   817;  load averages:  0.06,  0.36,  0.36    up 0+00:32:31
23:35:41
62 processes:  1 running, 61 sleeping
CPU states:  4.9% user,  0.0% nice,  7.1% system,  0.0% interrupt, 88.0%idle
Mem: 803M Active, 76M Inact, 88M Wired, 28M Cache, 109M Buf, 1656K Free
Swap: 998M Total, 234M Used, 765M Free, 23% Inuse, 3148K In, 2284K Out

PID USERNAME  THR PRI NICE   SIZE    RES STATE    TIME   WCPU COMMAND
751 root        1 -20    0   915M   756M swread   8:01  1.03% python