I seem to have hit the same issue as Fabio Brugnara http://www.ussg.iu.edu/hypermail/linux/kernel/0505.0/1061.html but although he said the problem went away for him in 2.6.11, I saw the problem in 2.6.8, and still see it in 2.6.14. When using a sliding mmap window over a file on nfs, the system time increases with time, and the throughput drops. Using the same program on a local file I get about 30MB/s with very little system time... just a bunch of iowait. I am using a gigabit connection to a netapp, and initially get 30+MB/s, but after about 30 seconds, this decays to only about 8MB/s with the system time close to 80%. I did a quick Oprofile run, and here is the top of the list: 1739810 16.8926 vmlinux-2.6.14 vmlinux-2.6.14 find_get_pages_tag 1305104 12.6718 vmlinux-2.6.14 vmlinux-2.6.14 mpage_writepages 1041147 10.1089 vmlinux-2.6.14 vmlinux-2.6.14 unlock_page 998692 9.6967 vmlinux-2.6.14 vmlinux-2.6.14 clear_page_dirty_for_io 966458 9.3838 vmlinux-2.6.14 vmlinux-2.6.14 release_pages 674434 6.5484 vmlinux-2.6.14 vmlinux-2.6.14 pci_conf1_write 486345 4.7221 vmlinux-2.6.14 vmlinux-2.6.14 __lookup_tag 399627 3.8801 vmlinux-2.6.14 vmlinux-2.6.14 page_waitqueue 134250 1.3035 vmlinux-2.6.14 vmlinux-2.6.14 _spin_lock_irqsave 130594 1.2680 vmlinux-2.6.14 vmlinux-2.6.14 _read_lock_irqsave I'm attaching the config. Other details: Dual Xeon 2.66 w/ 2GB RAM Debian sarge + 2.6.14 kernel + glibc 2.3.5 nvidia drivers broadcom gigabit driver (8.2.18) thanks, -Kenny __________________________________ Yahoo! FareChase: Search multiple travel sites in one click. http://farechase.yahoo.com
Attachment:
config-2.6.14
Description: 1636389412-config-2.6.14
- Prev by Date: Re: udev on 2.6.14 fails to create /dev/input/event2 on T40 Thinkpad
- Next by Date: Re: [2.6 patch] remove USB_AUDIO and USB_MIDI drivers
- Previous by thread: Re: + elevator-init-fixes.patch added to -mm tree
- Next by thread: re: mmap over nfs leads to excessive system load
- Index(es):
 |