Date: Mon, 28 Oct 2013 14:35:31 -0400 From: Allan Jude <freebsd@allanjude.com> To: freebsd-current@freebsd.org Subject: Re: ZFS txg implementation flaw Message-ID: <526EAE73.8040406@allanjude.com> In-Reply-To: <B1D05034-056B-4E0C-A52B-ECB8CA1F4F04@gmail.com> References: <20131028092844.GA24997@zxy.spb.ru> <0F1D571E-2806-4392-A5EC-BE66A3C92BF7@gmail.com> <20131028181631.GV63359@zxy.spb.ru> <B1D05034-056B-4E0C-A52B-ECB8CA1F4F04@gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On 2013-10-28 14:25, aurfalien wrote: > On Oct 28, 2013, at 11:16 AM, Slawa Olhovchenkov wrote: > >> On Mon, Oct 28, 2013 at 10:45:02AM -0700, aurfalien wrote: >> >>> On Oct 28, 2013, at 2:28 AM, Slawa Olhovchenkov wrote: >>> >>>> I can be wrong. >>>> As I see ZFS cretate seperate thread for earch txg writing. >>>> Also for writing to L2ARC. >>>> As result -- up to several thousands threads created and destoyed per >>>> second. And hundreds thousands page allocations, zeroing, maping >>>> unmaping and freeing per seconds. Very high overhead. >>>> >>>> In systat -vmstat I see totfr up to 600000, prcfr up to 200000. >>>> >>>> Estimated overhead -- 30% of system time. >>>> >>>> Can anybody implement thread and page pool for txg? >>> Would lowering vfs.zfs.txg.timeout be a way to tame or mitigate this? >> vfs.zfs.txg.timeout: 5 >> >> Only x5 lowering (less in real case with burst writing). And more fragmentation on writing and etc. > So leave it default in other words. > > Good to know. > > - aurf > > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" The default is the default for a reason, although the original default was 30 -- Allan Jude
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?526EAE73.8040406>