Re: High CPU utilization of hostap

From: Happy Camper (happy_programmer_at_yahoo.com)
Date: 2002-04-30 19:06:02 UTC

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Using this technique I do see a 10% improvement in CPU utilization on average. But the avg. CPU utilization of 25% on a P4 2GHz is still a cause for concern. Could this mean a potential 100% CPU utilization on a P3 500MHz?

Here is a capture of one of the top sessions during a large file download over my wireless connection that is using hostap_pci:

 11:50am up 21:58, 2 users, load average: 0.00, 0.01, 0.00 46 processes: 44 sleeping, 2 running, 0 zombie, 0 stopped CPU states: 0.0% user, 24.3% system, 0.0% nice, 75.6% idle Mem: 514136K av, 499112K used, 15024K free, 0K shrd, 81720K buff

Swap:  522104K av,       0K used,  522104K free                  229980K

  PID USER     PRI  NI  SIZE  RSS SHARE STAT %CPU %MEM   TIME COMMAND
    1 root      15   0   488  488   420 S     0.0  0.0   0:04 init
    2 root      15   0     0    0     0 SW    0.0  0.0   0:00 keventd
    3 root      15   0     0    0     0 SW    0.0  0.0   0:00 kapmd
    4 root      34  19     0    0     0 SWN   0.0  0.0   0:00
ksoftirqd_CPU0
    5 root      15   0     0    0     0 SW    0.0  0.0   0:00 kswapd
    6 root      25   0     0    0     0 SW    0.0  0.0   0:00 bdflush
    7 root      15   0     0    0     0 SW    0.0  0.0   0:00 kupdated
    8 root      25   0     0    0     0 SW    0.0  0.0   0:00 mdrecoveryd
   12 root      15   0     0    0     0 DW    0.0  0.0   0:00 kjournald
   91 root      15   0     0    0     0 SW    0.0  0.0   0:00 khubd
  701 root      15   0   576  576   488 S     0.0  0.1   0:00 syslogd
  706 root      15   0   444  444   384 S     0.0  0.0   0:00 klogd
  726 rpc       15   0   540  540   460 S     0.0  0.1   0:00 portmap
  754 rpcuser   17   0   708  708   612 S     0.0  0.1   0:00 rpc.statd
  901 root      15   0  1212 1212  1088 S     0.0  0.2   0:00 sshd
  958 root      15   0   516  516   452 S     0.0  0.1   0:00 gpm
  976 root      15   0   616  616   536 S     0.0  0.1   0:00 crond
 1044 xfs       15   0  5196 5196   872 S     0.0  1.0   0:00 xfs
 1080 daemon    15   0   516  516   452 S     0.0  0.1   0:00 atd
 1089 root      15   0   396  396   340 S     0.0  0.0   0:00 mingetty
 1090 root      15   0   396  396   340 S     0.0  0.0   0:00 mingetty
 1091 root      15   0   396  396   340 S     0.0  0.0   0:00 mingetty
 1092 root      15   0   396  396   340 S     0.0  0.0   0:00 mingetty
 2364 root      22   0   444  444   388 S     0.0  0.0   0:00 dhcpcd
 2473 root      18   0     0    0     0 SW    0.0  0.0   0:00 msp3410

Atif

• Jouni Malinen <jkmaline_at_cc.hut.fi> wrote:
  > On Mon, Apr 29, 2002 at 07:06:30PM -0700, Happy Camper wrote:
  >
  > > Downloaded the latest driver Prism2-2002-04-24.tar.gz and installed.
  > It
  > > all worked beautifully. Much much easier than I thought. I only have
  > one
  > > concern. The CPU utlization. It uses 40% of my 2GHz Intel P4 during
  > use.
  >
  > If you use the default configuration, TX path has a busy wait loop of
  > about 150 usec for every packet. This will use a lot of CPU no matter
  > how fast your CPU is..
  >
  > I have implemented alternative TX path handling that uses command
  > completion interrupt instead of busy wait. This should reduce the CPU
  > usage a lot, but it has not yet been fully tested so it is not the
  > default compilation option in the current release. If you would like
  > to test it, you can uncomment following line in
  > driver/modules/prism2_config.h:
  >
  > /* #define PRISM2_USE_CMD_COMPL_INTERRUPT */
  >
  > (i.e., change it into)
  >
  > #define PRISM2_USE_CMD_COMPL_INTERRUPT
  >
  >
  > --
  > Jouni Malinen PGP id EFC895FA
  >
  

  ---

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