HT scheduler: is it really correct? or is it feature of HT?
From: Tetsuji \"Maverick\" Rai
Date: Wed May 18 2005 - 13:45:04 EST
I'm wondering linux kernel's HT support is correct or not, or whether
it's a feature of P4 HT.
I'm running boinc/seti in the background with nice=19 on my P4 2.8G HT
enabled linux box, kernel 2.6.11.9, where SMT/HT is enabled.
I often watch system monitor applet on gnome desktop or top command in
a termianl window and see when no other applications than boinc is
running, boinc takes full power of both virtual cpus. It is designed
to run to "fill" the idle power of the cpu(s). However any
application is running, there is always some "idle" part appears on
virtual cpus, hence it looks like it wastes up to half of cpu power as
"idle."
For ex, see this "top" result while a vmware is running. (HT is
enabled) setiathome-4.7(blah--) are the background boinc applications
with nice=19.
-----------------------------------------------------------------
top - 03:21:30 up 1:58, 15 users, load average: 4.53, 4.56, 4.78
Tasks: 183 total, 5 running, 178 sleeping, 0 stopped, 0 zombie
Cpu0 : 0.3% us, 94.0% sy, 4.7% ni, 0.7% id, 0.0% wa, 0.3% hi, 0.0% si
Cpu1 : 2.7% us, 1.0% sy, 11.0% ni, 82.4% id, 3.0% wa, 0.0% hi, 0.0% si
Mem: 905068k total, 893584k used, 11484k free, 3840k buffers
Swap: 1662688k total, 0k used, 1662688k free, 526900k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
8490 tetsuji 25 0 205m 164m 154m R 93.7 18.7 75:10.29 vmware-vmx
7092 boinc 39 19 22828 18m 2012 R 5.6 2.1 27:22.04 setiathome-4.7.
8605 boinc 39 19 24992 20m 3212 R 5.6 2.3 20:58.46 setiathome-4.7.
7091 boinc 39 19 22696 18m 2012 R 4.7 2.1 27:01.92 setiathome-4.7.
7220 root 16 0 180m 32m 9396 S 1.3 3.6 3:23.59 X
7295 tetsuji 15 0 40936 28m 8356 S 1.3 3.2 0:38.64 gnome-terminal
8483 tetsuji 6 -10 205m 164m 154m S 0.7 18.7 1:04.59 vmware-vmx
7370 tetsuji 17 0 18348 9356 7176 S 0.3 1.0 0:09.53 clock-applet
-----------------------------------------------------------------
When HT is disabled, top looks like this: note idle is 0. nice fills
the vacant cpu power.
-----------------------------------------------------------------
top - 03:37:25 up 10 min, 13 users, load average: 5.31, 3.49, 1.66
Tasks: 137 total, 3 running, 134 sleeping, 0 stopped, 0 zombie
Cpu(s): 1.7% us, 43.9% sy, 51.2% ni, 0.0% id, 0.0% wa, 3.3% hi, 0.0% si
Mem: 905068k total, 895784k used, 9284k free, 1328k buffers
Swap: 1662688k total, 0k used, 1662688k free, 672892k cached
Change delay from 3.0 to:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
7350 boinc 39 19 22620 18m 2012 R 54.2 2.1 5:46.97 setiathome-4.7.
8126 tetsuji 15 0 93104 52m 47m S 35.2 6.0 1:14.76 vmware-vmx
8118 root 18 0 2200 876 724 R 5.7 0.1 0:13.71 tar
97 root 10 -5 0 0 0 S 1.0 0.0 0:02.98 kblockd/0
157 root 15 0 0 0 0 S 1.0 0.0 0:04.26 kswapd0
7169 root 15 0 171m 23m 7840 S 0.7 2.6 0:06.90 X
8166 root 15 0 0 0 0 S 0.7 0.0 0:00.06 pdflush
5182 root 15 0 0 0 0 S 0.3 0.0 0:02.84 kjournald
7242 tetsuji 15 0 29556 17m 8184 S 0.3 2.0 0:02.94 gnome-terminal
-----------------------------------------------------------------
Overall power is higher when HT is enabled, so I want to use it with HT enabled.
regards,
--
Luckiest in the world / Weapon of Mass Distraction
http://maverick6664.bravehost.com/
Aviation Jokes: http://www.geocities.com/tetsuji_rai/
Background: http://maverick.ns1.name/
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