ZFS slow reads for unallocated blocks
Andriy Gapon
avg at FreeBSD.org
Sat Apr 13 10:24:19 UTC 2013
on 13/04/2013 02:35 Adam Nowacki said the following:
> http://tepeserwery.pl/nowak/freebsd/zfs_sparse_optimization.patch.txt
>
> Does it look sane?
It's hard to tell from a quick look since they change is not small.
What is your idea of the problem and the fix?
> On 2013-04-12 09:03, Andriy Gapon wrote:
>>
>> ENOTIME to really investigate, but here is a basic profile result for those
>> interested:
>> kernel`bzero+0xa
>> kernel`dmu_buf_hold_array_by_dnode+0x1cf
>> kernel`dmu_read_uio+0x66
>> kernel`zfs_freebsd_read+0x3c0
>> kernel`VOP_READ_APV+0x92
>> kernel`vn_read+0x1a3
>> kernel`vn_io_fault+0x23a
>> kernel`dofileread+0x7b
>> kernel`sys_read+0x9e
>> kernel`amd64_syscall+0x238
>> kernel`0xffffffff80747e4b
>>
>> That's where > 99% of time is spent.
>>
>
--
Andriy Gapon
More information about the freebsd-fs
mailing list