Date: Wed, 30 Mar 2016 15:22:57 +0300 From: Ivan Klymenko <fidaj@ukr.net> To: Rick Miller <vmiller@hostileadmin.com> Cc: FreeBSD Questions <freebsd-questions@freebsd.org> Subject: Re: AIO Enabled? Message-ID: <20160330152257.599d068f@nonamehost.local> In-Reply-To: <CAHzLAVHx9o5PD45MUhnR28uZrxTGNCqd1eaQ0oqEYR1RaF85QQ@mail.gmail.com> References: <CAHzLAVHx9o5PD45MUhnR28uZrxTGNCqd1eaQ0oqEYR1RaF85QQ@mail.gmail.com>
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On Tue, 29 Mar 2016 14:42:57 -0400
Rick Miller <vmiller@hostileadmin.com> wrote:
> Hi all,
>
> I found old mail threads and blog posts (circa 2006 - 2010) that
> stated AIO is not enabled by default in FreeBSD. However, when
> running strings on the kernel, it appears AIO bits may be available...
>
> $ sudo strings -n3 /boot/kernel/kernel | grep -i aio
> aio_swake
> freebsd32_aio_read
> freebsd32_aio_write
> freebsd32_aio_return
> freebsd32_aio_suspend
> freebsd32_aio_cancel
> freebsd32_aio_error
> freebsd32_oaio_read
> freebsd32_oaio_write
> freebsd32_aio_waitcomplete
> freebsd32_aio_fsync
> freebsd32_aio_mlock
> AIOSTOP: bad channel 0x%x
> AIOSYNC chan 0x%03lx pos %lu unimplemented
> AIONWRITE
> AIOGSIZE
> AIOSSIZE
> AIOGFMT
> AIOSFMT
> AIOGMIX
> AIOSMIX
> AIOSTOP
> AIOSYNC
> AIOGCAP
> nfsaio
> aio_prio_delta_max
> aio_max
> aio_listio_max
>
> aio(4) states it can be linked in the kernel using options VFS_AIO or
> dynamically using loader.conf or kldload suggesting it still is not
> enabled by default. This brings me to a couple questions I hope are
> easily answered.
>
> 1) Is AIO still disabled by default in FreeBSD 10.x and newer?
> 2) Does strings send the same output above to STDOUT irregardless of
> whether AIO is enabled/disabled?
>
>
> Thanks.
>
for CURRENT
/usr/src/UPDATING
...
20160301:
The AIO subsystem is now a standard part of the kernel. The
VFS_AIO kernel option and aio.ko kernel module have been removed.
Due to stability concerns, asynchronous I/O requests are only
permitted on sockets and raw disks by default. To enable
asynchronous I/O requests on all file types, set the
vfs.aio.enable_unsafe sysctl to a non-zero value.
...
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