did something change in SMP scheduling from 5.4 to 6.0?
Randy Schultz
schultz at sgi.com
Thu Jan 26 09:05:38 PST 2006
Hey all,
I am curious if something changed in the way extra cpus are utilized in 6.0
vs. 5.4 in a SMP kernel.
My system is a dual-proc Xeon box. When I was using 5.4 top would show
both procs being used roughly the same, e.g. the "C" column usually had
almost as many processes running on the second cpu as on the first. On
Jan 23 I did a cvsup and compiled a new 6.0-STABLE SMP kernel. Now
watching top I rarely see the second proc being used, even though
roundrobin is enabled. FWIW, here's some possibly relevant config bits:
Dude ? sysctl -a|egrep smp
kern.timecounter.smp_tsc: 0
kern.smp.forward_roundrobin_enabled: 1
kern.smp.forward_signal_enabled: 1
kern.smp.cpus: 4
kern.smp.disabled: 0
kern.smp.active: 1
kern.smp.maxcpus: 16
Dude ?
Dude ? sysctl -a|egrep hyperth
machdep.hyperthreading_allowed: 0
I've attached the output of a typical top with some builds running.
Unfortunately I don't have any saved data from 5.4.
I do see the second processor being used but those times are rare. When it
does happen it seems almost exclusively when I'm seriously hammering the
system. This makes me think something has changed with 6.0 behind-the-scenes
such that if the system doesn't need the extra power then it sticks to cpu 0.
I poked around the release notes and handbook but failed to find anything
on this topic. Am I all wet and simply have something misconfigured or
indeed all is well with 6.x doing it's thing hugging cpu 0?
--
Randy (schultz at sgi.com) 715-726-2832 email bodhisattva <*>
"There is no fire like passion, there is no shark like hatred,
there is no snare like folly, there is no torrent like greed."
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last pid: 86336; load averages: 0.37, 0.31, 0.22 up 2+22:34:02 10:21:42
148 processes: 2 running, 146 sleeping
CPU states: 14.9% user, 0.0% nice, 10.2% system, 0.0% interrupt, 74.8% idle
Mem: 312M Active, 963M Inact, 187M Wired, 11M Cache, 112M Buf, 529M Free
Swap: 4096M Total, 4096M Free
PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND
86122 root 1 8 0 1612K 1500K wait 0 0:00 16.50% make
86335 root 1 139 0 584K 476K RUN 0 0:00 16.50% make
86288 root 1 -8 0 1648K 1184K piperd 0 0:00 16.50% sh
85738 root 1 -8 0 21276K 20924K piperd 0 0:02 14.99% ruby18
86121 root 1 8 0 1636K 1172K wait 0 0:00 14.99% sh
655 schultz 1 76 0 30148K 29220K select 0 15:43 0.00% Xorg
11160 schultz 1 76 0 2644K 1924K select 0 2:20 0.00% top
80862 schultz 7 20 0 203M 190M kserel 0 2:06 0.00% firefox-bin
667 schultz 1 76 0 14136K 10276K select 0 0:32 0.00% xchat
4023 schultz 1 76 0 6924K 5948K select 0 0:31 0.00% xterm-static
3013 schultz 8 20 0 55640K 41624K kserel 0 0:29 0.00% evolution-2.2
4006 schultz 1 76 0 5468K 4492K select 0 0:25 0.00% xterm-static
801 schultz 1 76 0 5472K 4496K select 0 0:20 0.00% xterm-static
592 root 1 76 0 1216K 676K select 0 0:19 0.00% moused
41670 schultz 1 76 0 8672K 6968K select 0 0:15 0.00% pine
692 schultz 1 76 0 5484K 4424K select 0 0:11 0.00% xterm-static
10846 schultz 1 76 0 5452K 4460K select 0 0:10 0.00% xterm-static
708 schultz 1 76 0 5500K 4524K select 0 0:09 0.00% xterm-static
1172 schultz 1 76 0 5452K 4476K select 0 0:09 0.00% xterm-static
80886 schultz 1 76 0 2632K 1912K CPU0 0 0:08 0.00% top
494 root 1 76 0 2924K 1760K select 0 0:08 0.00% ntpd
888 schultz 1 76 0 5452K 4448K select 0 0:07 0.00% xterm-static
660 schultz 1 76 0 5400K 3548K select 0 0:06 0.00% fvwm
12259 schultz 1 76 0 5472K 4496K select 0 0:05 0.00% xterm-static
81573 schultz 1 76 0 5468K 4492K select 0 0:05 0.00% xterm-static
20918 schultz 1 76 0 5500K 4524K select 0 0:05 0.00% xterm-static
32772 schultz 1 76 0 5452K 4448K select 0 0:05 0.00% xterm-static
385 root 1 76 0 1300K 828K select 0 0:04 0.00% syslogd
9622 schultz 1 76 0 5468K 4504K select 0 0:03 0.00% xterm-static
9287 schultz 1 76 0 5468K 4504K select 0 0:03 0.00% xterm-static
14583 schultz 1 76 0 5500K 4536K select 0 0:02 0.00% xterm-static
20866 schultz 1 76 0 5480K 4512K select 0 0:02 0.00% xterm-static
20907 schultz 1 76 0 5468K 4504K select 0 0:02 0.00% xterm-static
688 schultz 1 76 0 4888K 3680K select 0 0:02 0.00% gconfd-2
664 schultz 1 76 0 4664K 3040K select 0 0:02 0.00% FvwmPager
3018 schultz 7 20 0 32768K 18764K kserel 0 0:02 0.00% evolution-alar
45374 schultz 1 139 0 3336K 2780K select 0 0:01 0.00% ssh
662 schultz 1 76 0 4844K 3992K select 0 0:01 0.00% xclock
3015 schultz 8 20 0 19500K 13188K kserel 0 0:01 0.00% evolution-data
533 root 1 8 0 1336K 1004K nanslp 0 0:01 0.00% cron
465 root 1 76 0 1216K 760K select 0 0:00 0.00% usbd
663 schultz 1 76 0 4636K 3016K select 0 0:00 0.00% FvwmButtons
85699 schultz 1 76 0 5472K 4508K select 0 0:00 0.00% xterm-static
69066 schultz 1 76 0 6284K 3244K select 0 0:00 0.00% sshd
24786 schultz 1 76 0 3416K 2784K select 0 0:00 0.00% ssh
82035 schultz 1 76 0 3604K 3004K select 0 0:00 0.00% ssh
75451 schultz 1 76 0 3292K 2732K select 0 0:00 0.00% ssh
16459 schultz 1 139 0 3428K 2792K select 0 0:00 0.00% ssh
517 root 1 20 0 3424K 2776K pause 0 0:00 0.00% sendmail
521 smmsp 1 20 0 3304K 2672K pause 0 0:00 0.00% sendmail
3533 schultz 1 76 0 6084K 3096K select 0 0:00 0.00% sshd
864 schultz 1 139 0 5452K 3740K select 0 0:00 0.00% bonobo-activat
85713 schultz 1 76 0 3292K 2744K select 0 0:00 0.00% ssh
68864 schultz 1 76 0 3292K 2772K select 0 0:00 0.00% ssh
79603 schultz 1 76 0 3292K 2740K select 0 0:00 0.00% ssh
33080 schultz 1 76 0 3292K 2768K select 0 0:00 0.00% ssh
79588 schultz 1 76 0 6084K 3128K select 0 0:00 0.00% sshd
33049 schultz 1 76 0 6084K 3112K select 0 0:00 0.00% sshd
79602 schultz 1 139 0 3292K 2740K select 0 0:00 0.00% ssh
85615 schultz 1 76 0 3292K 2744K select 0 0:00 0.00% ssh
3769 schultz 1 76 0 3292K 2712K select 0 0:00 0.00% ssh
69050 root 1 4 0 6104K 3120K sbwait 0 0:00 0.00% sshd
33040 root 1 4 0 6104K 3104K sbwait 0 0:00 0.00% sshd
79571 root 1 4 0 6104K 3120K sbwait 0 0:00 0.00% sshd
79568 root 1 4 0 6104K 3120K sbwait 0 0:00 0.00% sshd
4038 root 1 20 0 856K 620K pause 0 0:00 0.00% ksh
33046 root 1 4 0 6104K 3104K sbwait 0 0:00 0.00% sshd
3755 root 1 4 0 6108K 3088K sbwait 0 0:00 0.00% sshd
3530 root 1 4 0 6104K 3088K sbwait 0 0:00 0.00% sshd
709 schultz 1 20 0 872K 648K pause 0 0:00 0.00% ksh
79628 schultz 1 76 0 3292K 2780K select 0 0:00 0.00% ssh
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