Re: SCHEDULE and high load situations

On 11 Aug, To: rwatson_at_freebsd.org wrote:

> I've noticed in fork()/exec() intensive loads like buildworld and
> building ports on a UP box that ULE favors a CPU-bound but niced process
> like setiathome over the software build.  Even the longer c++ compile
> steps seem to get less CPU time, than the niced CPU-bound process, at
> least according to top.  Buildworld times with ULE on my Athlon XP box
> are about 145 minutes with ULE and 82 minutes with 4BSD when competing
> with setiathome.  Top shows setiathome consistently getting about 55% of
> the CPU with ULE.  Without setiathome running, buildworld takes about 65
> minutes.

Here's a case where there is not much fork()/exec() activity (last pid
is stable), and there doesn't appear to be much I/O, but the niced
process is getting more than 50% of the CPU.  I noticed this during a
portupgrade of editors/openoffice-1.1.  The CPU% for setiathome seems to
stay right around in this range +/- a percent or so, with spikes higher
when the other processes normally competing for CPU time are waiting for
I/O.

57 processes:  3 running, 53 sleeping, 1 stopped
CPU states: 42.8% user, 56.0% nice,  1.2% system,  0.0% interrupt,  0.0% idle
Mem: 99M Active, 628M Inact, 156M Wired, 31M Cache, 111M Buf, 83M Free
Swap: 2055M Total, 84K Used, 2055M Free
Seconds to delay:
  PID USERNAME   PRI NICE   SIZE    RES STATE    TIME   WCPU    CPU COMMAND
  504 setiathome 139   15 17744K 16884K RUN    719:22 54.69% 54.69% setiathome
64008 root       139    0  4232K  3832K RUN     11:50 41.41% 41.41% dmake
  568 dl          76    0  6084K  2324K select   5:08  0.00%  0.00% sshd
  483 uucp        76    0  1336K   988K select   2:36  0.00%  0.00% newapc
16995 root        76    0  1284K   760K select   2:21  0.00%  0.00% script
12823 root        -8    0  1200K   552K piperd   2:03  0.00%  0.00% tee
  485 uucp        76    0  1308K   944K select   0:33  0.00%  0.00% upsd
53855 root         8    0  4956K  4212K wait     0:13  0.00%  0.00% perl
  489 uucp         8    0  1316K  1012K nanslp   0:12  0.00%  0.00% upsmon
  410 root        76    0  2876K  1500K select   0:10  0.00%  0.00% ntpd
59764 dl          76    0  2400K  1604K RUN      0:07  0.00%  0.00% top
  437 root        76    0  3436K  2300K select   0:05  0.00%  0.00% sendmail
12822 root         8    0 21348K 20792K wait     0:02  0.00%  0.00% ruby18
  490 uucp         8    0  1272K   908K nanslp   0:01  0.00%  0.00% upslog
 1101 dl          76    0  6084K  2324K select   0:01  0.00%  0.00% sshd
  454 root         8    0  1356K  1004K nanslp   0:01  0.00%  0.00% cron
  657 root        20    0  2440K  1940K pause    0:01  0.00%  0.00% csh