From Bugzilla Helper: User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.6) Gecko/20040206 Firefox/0.8 Description of problem: Hardware is Pentium 4 HT capable 2.8Ghz on Abit IC7 Max3 motherboard. (which is intel 875 chipset) with 1gig of ram. If I boot the smp kernel then hdparm and normal file access to files on /dev/md0 mounted as /raid. Raid is 6 200gig sata drives in raid 5 128k chunk filesystem is ext3 block size is 2048 stride is set to 64. (created with mdadm and started with it) Using default kernels on fc2 test3 release 2.6.5-1.327 and 2.6.5-1.327smp. hdparm -Tt /dev/md0 under smp - is 15-22 megabytes/sec hdparm -Tt /dev/md0 under single cpu - is over 100 megabytes/sec Reading a 3 gigabyte file from /raid shows an equivalent different in performance under the smp and single kernels. hdparm any of the 6 raw drives in the md0 raid. hdparm -Tt /dev/sda1 - gives around 48 megabytes sec in either the smp or the single cpu kernel. It appears just the software raid device is having some sort of problem. I cannot find any errors appearing in the logs (though maybe i just dont know all the places to look). If I boot the smp kernel with acpi=off and apm=off then smp kernel appears to give same sort of performance as single cpu. Version-Release number of selected component (if applicable): mdadm-1.5.0-3 How reproducible: Always Steps to Reproduce: 1. boot smp kernel 2. hdparm -Tt /dev/md0 3. Actual Results: Its much slower in performance than in single cpu kernel or with acpi=off apm=off. Additional info:
Please attach the dmesg and /proc/interrupts from the successful UP kernel, and failing MP kernel. It may be an IOAPIC issue, since that comes along with the SMP kernel.
Closing this bug due to inactivity.