Dear Sirs, I am having a problem of low computational speed. The command dmesg has given a message "An unexpected IO-APIC was found" recommending that it be e-mailed to you. The complete dmesg is attached to this e-mail. I also include the text of a message that I have sent to Support SUSE LINUX AG which may further illuminate the problem. *********** Text sent to SUSE support ************** I have an old 500MHz Pentium 3 running SuSE Linux 7.1 (kernel 2.4.0). I needed to speed up the execution of a numerical algorithm running in scilab, so I put together a 3GHz P4 XEON APIC v16 on a Shuttle FB61 main board with SuSE Linux 9.0 (kernel 2.4.21-99 SMP4G). To my surprise, the *old* P3 system runs the scilab program *faster* than the new P4. The vmstat command gives the following CPU information when the scilab program is iterating. ----- cpu ----- us sy id wa P3 82 18 0 P4 8 43 49 0 top gives: P4 without scilab: 0.5% user, 40.1% system, 0.0% nice, 59.9% idle P4 with scilab: 30% user, 50% system, 0.0% nice, 20% idle P3 without scilab: 0.3% user, 0.1% system, 0.0% nice, 99.4% idle P3 with scilab: 83% user, 17% system, 0.0% nice, 0% idle Also, the times for running scilab on the P4 vary from run to run. The scilab test runs for 19 iterations of my algorithm. On one run this took 42sec and on the next run with the same data 80sec. On the 80sec run top was showing user time falling to 8% after a while whilst the system was always around 50% with idle taking up the difference. I don't know if this is significant, but the result of the command dmesg gives a lot of information, and within this information is the message "An unexpected IO-APIC was found. If this kernel release is less than three months old please report this to linux-smp@vger.kernel.org". Here is the fragment from dmesg surrounding the message. IO APIC #2...... .... register #00: 02000000 ....... : physical APIC id: 02 ....... : Delivery Type: 0 ....... : LTS : 0 .... register #01: 00178020 ....... : max redirection entries: 0017 ....... : PRQ implemented: 1 ....... : IO APIC version: 0020 .... register #02: 00178020 ....... : arbitration: 00 An unexpected IO-APIC was found. If this kernel release is less than three months old please report this to linux-smp@vger.kernel.org .... IRQ redirection table: NR Log Phy Mask Trig IRR Pol Stat Dest Deli Vect: 00 000 00 1 0 0 0 0 0 0 00 01 003 03 0 0 0 0 0 1 1 39 The complete result of dmesg is attached to this e-mail. ***************** End of text ****************** Yours sincerely Stephen Blake