Re: Fw: Regression with hyper threading scheduling

From: Wolfgang Erig
Date: Mon Aug 21 2006 - 06:52:55 EST


On Sun, Aug 20, 2006 at 06:04:00PM +1000, Peter Williams wrote:
> ...
> >lshw
> > description: Mini Tower Computer
> > product: SCENIC P / SCENICO P
> > vendor: FUJITSU SIEMENS
> > version: SCEP
> > serial: YBEM738326
> > width: 32 bits
> > capabilities: smbios-2.31 dmi-2.31
> > configuration: boot=normal chassis=mini-tower
> > uuid=FA48F283-A977-D811-A847-912FD384AB1D
> > *-core
> > description: Motherboard
> > product: D1561
> > vendor: FUJITSU SIEMENS
> > physical id: 0
> > version: S26361-D1561
> > slot: Serial-1
> > *-firmware
> > description: BIOS
> > vendor: FUJITSU SIEMENS // Phoenix Technologies Ltd.
> > physical id: 0
> > version: 5.00 R2.14.1561.01 (11/25/2004)
> > size: 109KB
> > capacity: 448KB
> > capabilities: pci pnp apm upgrade shadowing escd cdboot
> > bootselect int13floppynec int13floppytoshiba int13floppy360
> > int13floppy1200 int13floppy720 int13floppy2880 int5printscreen
> > int9keyboard int14serial int17printer int10video acpi usb agp
> > ls120boot zipboot biosbootspecification
> > *-cpu
> > description: CPU
> > product: Intel(R) Pentium(R) 4 CPU 2.60GHz
> > vendor: Intel Corp.
> > physical id: 4
> > bus info: cpu@0
> > version: 15.2.9
> > slot: CPU
> > size: 2600MHz
> > capacity: 2600MHz
> > width: 32 bits
> > clock: 800MHz
> > capabilities: fpu fpu_exception wp vme de pse tsc msr pae mce
> > cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx
> > fxsr sse sse2 ss ht tm pbe cid
> > configuration: id=1
> ...
>
> I'm unable to reproduce this problem with 2.6.18-rc4 on my HT system.
> I'm using top with the "last processor" field enabled to observe (rather
> than the methods described) and the two bash shells are both getting
> 100% and are each firmly affixed to different CPUs.

We can see the problem only on the hardware above.
Another (newer) system runs perfectly:

lshw
description: Mini Tower Computer
product: SCENIC P / SCENICO P
vendor: FUJITSU SIEMENS
version: SCEP2
serial: YBPB012753
width: 32 bits
capabilities: smbios-2.31 dmi-2.31
configuration: boot=normal chassis=mini-tower
uuid=F5585067-4E15-11D9-897B-0030057E3EC7
*-core
description: Motherboard
product: D1931
vendor: FUJITSU SIEMENS
physical id: 0
version: S26361-D1931
serial: 16105060
slot: Serial-1
*-firmware
description: BIOS
vendor: FUJITSU SIEMENS // Phoenix Technologies Ltd.
physical id: 0
version: 5.00 R1.08.1931 (12/03/2004)
size: 110KB
capacity: 448KB
capabilities: pci pnp apm upgrade shadowing escd cdboot
bootselect int13floppynec int13floppytoshiba int13floppy360
int13floppy1200 int13floppy720 int13floppy2880 int5printscreen
int9keyboard int14serial int17printer int10video acpi usb agp
ls120boot zipboot biosbootspecification
*-cpu
description: CPU
product: Intel(R) Pentium(R) 4 CPU 3.20GHz
vendor: Intel Corp.
physical id: 4
bus info: cpu@0
version: 15.4.1
serial: 0000-0F41-0000-0000-0000-0000
slot: CPU
size: 3200MHz
capacity: 3200MHz
width: 32 bits
clock: 800MHz
capabilities: fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx constant_tsc pni monitor ds_cpl cid xtpr
configuration: id=0
...

Wolfgang
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