svn commit: r278040 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs

[Steven Hartland]

On 02/02/2015 00:28, Davide Italiano wrote:
> On Mon, Feb 2, 2015 at 1:17 AM, Steven Hartland <smh at freebsd.org> wrote:
>> Author: smh
>> Date: Mon Feb  2 00:17:36 2015
>> New Revision: 278040
>> URL: https://svnweb.freebsd.org/changeset/base/278040
>>
>> Log:
>>    Prevent inlining txg_quiesce
>>
>>    This allows dtrace to monitor the calls to txg_quiesce which can be really
>>    helpful.
>>
>>    Also standardise __noinline order for arc_kmem_reap_now.
>>
>>    Sponsored by: Multiplay
>>
>>
> I found this while I was at iXsystems, trying to port Richard Elling's
> arc statistics utility to FreeBSD.
> I do not disagree with the change in theory, but I never committed
> this because I was worried of performance penalty.
> Last time I checked Solaris/Illumos actually do not inline this
> function without any particular directive (I guess this is mostly due
> to difference in toolchain, in particular in the compiler), so it
> shouldn't be a big deal, but if you have time, do you mind to check
> the penalty introduced, if any, is negligible?
Performance difference should be negligible if not unmeasurable, but 
I'll run some tests to check call frequency to be sure.

 From what I can tell its inlined because there is only a single caller 
(txg_quiesce_thread).

     Regards
     Steve