Date: Wed, 14 Sep 2005 19:46:12 +0200 From: Oliver Lehmann <lehmann@ans-netz.de> To: current@freebsd.org Subject: low(er) disk performance with sched_4bsd then with sched_ule Message-ID: <20050914194612.15692485.lehmann@ans-netz.de>
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Hi, I've a dual-cpu system (SMP) which runs with 2 PIII-850 MHz on an Intel Serverboard (440GX chipset). My diskspace is provided by a RAID-5 containing 4 WD2500KS harddrives connected to a 3ware 9500S-4LP controller which runs at 32bit/33MHz. The system itself runs FreeBSD 6.0-BETA2. with SCHED_4BSD in the kernel: root@nudel olivleh1> dd if=/dev/zero of=/mnt/files/test.dd bs=64k count=32000 32000+0 records in 32000+0 records out 2097152000 bytes transferred in 44.136711 secs (47514913 bytes/sec) with SCHED_ULE in the kernel: root@nudel olivleh1> dd if=/dev/zero of=/mnt/files/test.dd bs=64k count=32000 32000+0 records in 32000+0 records out 2097152000 bytes transferred in 27.005334 secs (77656954 bytes/sec) the scheduler is the only difference between both configs - everything else is the same. Kernel debugging is disabled, malloc.conf exists. Filesystem Size Used Avail Capacity Mounted on /dev/da0s1a 496M 159M 297M 35% / devfs 1.0K 1.0K 0B 100% /dev /dev/da0s1d 496M 20M 436M 4% /var /dev/da0s1e 496M 22M 434M 5% /tmp /dev/da0s1f 19G 2.9G 15G 16% /usr /dev/da0s1g 671G 216G 455G 32% /mnt/files 3ware device driver for 9000 series storage controllers, version: 3.60.00.017 twa0: <3ware 9000 series Storage Controller> port 0x3400-0x34ff mem 0xf4102800-0xf41028ff,0xf4800000-0xf4ffffff irq 16 at device 16.0 on pci0 twa0: [FAST] twa0: INFO: (0x15: 0x1300): Controller details:: 4 ports, Firmware FE9X 2.08.00.005, BIOS BE9X 2.03.01.052 da0 at twa0 bus 0 target 0 lun 0 da0: <AMCC 9500S-4LP DISK 2.08> Fixed Direct Access SCSI-3 device da0: 100.000MB/s transfers da0: 715224MB (1464778752 512 byte sectors: 255H 63S/T 91178C) Any idea where the 30MB/sec drawback comes from and if I missed sth.? I mean why there are 30MB/s more or less is worth to think about imho. -- Oliver Lehmann http://www.pofo.de/ http://wishlist.ans-netz.de/
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