Re: HDD write cache
On Sat, 2 Feb 2013 01:19:50 +0100 (CET) Wojciech Puchar woj...@wojtek.tensor.gdynia.pl wrote: Investigating a bit more a device reset will also trigger the change so after changing the value you can use camcontrol reset to trigger the change to apply using e.g. camcontrol reset 0:0:0 THIS actually work. And the results are disastrous. in spite of NCQ working and fully filled, when unpacking source tree (as a test) onto UFS filesystem gstat shows at most 100 IOPS, and average 700 with write cache disabled. this is on / partition that spans 1/10 of disk. Drive can actually manage multiple writes in short distance well with write cache enabled. I also noticed a drastic drop in throughput when I disabled the write cache, about a factor of 4 or 5. However, in my case every HDD supports NCQ (32 tags), but NCQ is not enabled on any HDD. Whether that's because the driver for my chipset (ATI IXP700 AHCI SATA controller) doesn't turn NCQ on or for another reason, I can't say. I looked at the man page for camcontrol but a mechanism to turn on NCQ in the HDDs didn't jump off the page. Does anyone know off-hand of a way to turn on NCQ in the HDDs, other than maybe modifying the driver? -- Gary Jennejohn ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: Failsafe on kernel panic
On 1/20/13 6:07 PM, Willem Jan Withagen wrote: On 17-1-2013 4:18, Ian Lepore wrote: On Wed, 2013-01-16 at 23:27 +0200, Sami Halabi wrote: Thank you for your response, very helpful. one question - how do i configure auto-reboot once kernel panic occurs? Sami From src/sys/conf/NOTES, this may be what you're looking for... # # Don't enter the debugger for a panic. Intended for unattended operation # where you may want to enter the debugger from the console, but still want # the machine to recover from a panic. # options KDB_UNATTENDED But I think it only has meaning if you have option KDB in effect, otherwise it should just reboot itself after a 15 second pause. Well it is not the magical fix-all solution. Last night I had to drive to the colo (lucky for me a 5 min drive.) because I could not get a system to reboot/recover from a crash. Upon arrival the system was crashed and halted on the message: rebooting in 15 sec. I've seen the same thing many and many times. Now I'm using ddb to save crash dump and reboot machine on panic. It's much more reliable. -- Andrey Zonov signature.asc Description: OpenPGP digital signature
Re: some questions on kern_linker and pre-loaded modules
on 28/01/2013 17:40 John Baldwin said the following: Yes, I think it is too hard at present to safely allow a linker file to override the same module in a kernel, so the duplicate linker file should just be rejected entirely. I'm not sure if your change is completely correct for that. Incidentally that particular patch was broken. Here is a working patch: http://people.freebsd.org/~avg/linker_file_register_modules-linker_kernel_file.diff But I really need to get a better understanding of the bigger picture and then discuss what has to be done in that scope. I plan to write a larger response to your complete followup. Thank you. -- Andriy Gapon ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
scheduler-swapper, SI_SUB_RUN_SCHEDULER-SI_SUB_LAST
I would like to propose the following mostly cosmetic change: http://people.freebsd.org/~avg/scheduler-swapper.diff This is something that bit me early in my FreeBSD days, so I am kind of obsessed with it. The current naming is confusing/misleading indeed. And magic properties of SI_SUB_RUN_SCHEDULER:SI_ORDER_LAST is a hidden gem. -- Andriy Gapon ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: scheduler-swapper, SI_SUB_RUN_SCHEDULER-SI_SUB_LAST
On Sat, Feb 02, 2013 at 01:50:40PM +0200, Andriy Gapon wrote: I would like to propose the following mostly cosmetic change: http://people.freebsd.org/~avg/scheduler-swapper.diff This is something that bit me early in my FreeBSD days, so I am kind of obsessed with it. The current naming is confusing/misleading indeed. And magic properties of SI_SUB_RUN_SCHEDULER:SI_ORDER_LAST is a hidden gem. You may remove the Giant unlock from the scheduler()/swapper() as well then, doing it before the swapper() call in the mi_startup(). Note that the wait chain for the idle swapper is still called sched. pgp0gyHIR2xWU.pgp Description: PGP signature
backport RSU from OpenBSD
Hello people, I notice you i am trying to import RSU driver from OpenBSD. a diff will be available later. Loïc BLOT ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
