Messages in this thread |  | | | Date | Sun, 20 Aug 2006 18:04:00 +1000 | | From | Peter Williams <> | | Subject | Re: Fw: Regression with hyper threading scheduling |
Andrew Morton wrote: > fyi.. (if replying, please be sure to do it on-list) > > Begin forwarded message: > > Date: Thu, 17 Aug 2006 13:40:42 +0200 > From: Wolfgang Erig <Wolfgang.Erig@gmx.de> > To: linux-kernel@vger.kernel.org > Cc: andreas.friedrich@fujitsu-siemens.com > Subject: Regression with hyper threading scheduling > > > Hello kernel hacker, > > I have a regression with Hyper-Threading in my box. > > If I try e.g. 'while true; do ((ii+=1)); done' on two xterms > - with 2.6.8 both CPUs are running (looking at gkrellm or /proc/stat) > - with 2.6.15/2.6.17 etc. only one CPU is running, sometimes CPU0, sometimes CPU1 > > Any idea? If you need more info, let me know, > Wolfgang > > > Kernel 2.6.8.1: Hyper-Threading works: > ====================================== > uname -a > Linux oak 2.6.8.1 #1 SMP Wed May 10 13:24:21 CEST 2006 i686 GNU/Linux > > cat /proc/stat > cpu 22709 4502 2543 1008491 2881 92 1475 > cpu0 12800 2428 1426 501276 1859 92 1472 > cpu1 9909 2074 1117 507215 1021 0 2 > intr 5909520 5214423 7297 0 2 2 0 2 1 0 0 0 0 92935 0 7422 13 0 224861 42603 0 0 0 319959 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 > ctxt 6553093 > btime 1155801409 > processes 2525 > procs_running 3 > procs_blocked 0 > > Kernel 2.6.17.8 etc.: Hyper-Threading does not work: > ==================================================== > uname -a > Linux oak 2.6.17.8 #2 SMP PREEMPT Thu Aug 17 11:40:04 CEST 2006 i686 GNU/Linux > > cat /proc/stat > cpu 5049 0 744 137292 3113 18 3 0 > cpu0 36 0 53 72732 282 18 1 0 > cpu1 5012 0 690 64560 2831 0 2 0 > intr 221093 182798 880 0 3 4 0 3 1 0 0 0 0 28863 0 6718 12 1811 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 > ctxt 458461 > btime 1155807757 > processes 3203 > procs_running 1 > procs_blocked 0 > > Some HW-Infos: > ============== > 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 > *-cache:0 > description: L1 cache > physical id: 5 > slot: L1 Cache > size: 8KB > capacity: 32KB > capabilities: burst synchronous internal write-through data > *-cache:1 > description: L2 cache > physical id: 6 > slot: L2 Cache > size: 512KB > capacity: 1MB > capabilities: burst internal write-back unified > *-cache:2 DISABLED > description: L3 cache > physical id: 7 > slot: L3 Cache > capacity: 16MB > capabilities: internal write-back unified > *-logicalcpu:0 > description: Logical CPU > physical id: 1.1 > width: 32 bits > capabilities: logical > *-logicalcpu:1 > description: Logical CPU > physical id: 1.2 > width: 32 bits > ...
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.
Peter -- Peter Williams pwil3058@bigpond.net.au
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