RE: OpTracker optimization

[Sage Weil <sweil@redhat.com>]

I had two substantiative comments on the first patch and then some trivial 
whitespace nits.    Otherwise looks good!

tahnks-
sage

On Thu, 11 Sep 2014, Somnath Roy wrote:

> Sam/Sage,
> I have incorporated all of your comments. Please have a look at the same pull request.
> 
> https://github.com/ceph/ceph/pull/2440
> 
> Thanks & Regards
> Somnath
> 
> -----Original Message-----
> From: Samuel Just [mailto:sam.just@inktank.com] 
> Sent: Wednesday, September 10, 2014 3:25 PM
> To: Somnath Roy
> Cc: Sage Weil (sweil@redhat.com); ceph-devel@vger.kernel.org; ceph-users@lists.ceph.com
> Subject: Re: OpTracker optimization
> 
> Oh, I changed my mind, your approach is fine.  I was unclear.
> Currently, I just need you to address the other comments.
> -Sam
> 
> On Wed, Sep 10, 2014 at 3:13 PM, Somnath Roy <Somnath.Roy@sandisk.com> wrote:
> > As I understand, you want me to implement the following.
> >
> > 1.  Keep this implementation one sharded optracker for the ios going through ms_dispatch path.
> >
> > 2. Additionally, for ios going through ms_fast_dispatch, you want me 
> > to implement optracker (without internal shard) per opwq shard
> >
> > Am I right ?
> >
> > Thanks & Regards
> > Somnath
> >
> > -----Original Message-----
> > From: Samuel Just [mailto:sam.just@inktank.com]
> > Sent: Wednesday, September 10, 2014 3:08 PM
> > To: Somnath Roy
> > Cc: Sage Weil (sweil@redhat.com); ceph-devel@vger.kernel.org; 
> > ceph-users@lists.ceph.com
> > Subject: Re: OpTracker optimization
> >
> > I don't quite understand.
> > -Sam
> >
> > On Wed, Sep 10, 2014 at 2:38 PM, Somnath Roy <Somnath.Roy@sandisk.com> wrote:
> >> Thanks Sam.
> >> So, you want me to go with optracker/shadedopWq , right ?
> >>
> >> Regards
> >> Somnath
> >>
> >> -----Original Message-----
> >> From: Samuel Just [mailto:sam.just@inktank.com]
> >> Sent: Wednesday, September 10, 2014 2:36 PM
> >> To: Somnath Roy
> >> Cc: Sage Weil (sweil@redhat.com); ceph-devel@vger.kernel.org; 
> >> ceph-users@lists.ceph.com
> >> Subject: Re: OpTracker optimization
> >>
> >> Responded with cosmetic nonsense.  Once you've got that and the other comments addressed, I can put it in wip-sam-testing.
> >> -Sam
> >>
> >> On Wed, Sep 10, 2014 at 1:30 PM, Somnath Roy <Somnath.Roy@sandisk.com> wrote:
> >>> Thanks Sam..I responded back :-)
> >>>
> >>> -----Original Message-----
> >>> From: ceph-devel-owner@vger.kernel.org 
> >>> [mailto:ceph-devel-owner@vger.kernel.org] On Behalf Of Samuel Just
> >>> Sent: Wednesday, September 10, 2014 11:17 AM
> >>> To: Somnath Roy
> >>> Cc: Sage Weil (sweil@redhat.com); ceph-devel@vger.kernel.org; 
> >>> ceph-users@lists.ceph.com
> >>> Subject: Re: OpTracker optimization
> >>>
> >>> Added a comment about the approach.
> >>> -Sam
> >>>
> >>> On Tue, Sep 9, 2014 at 1:33 PM, Somnath Roy <Somnath.Roy@sandisk.com> wrote:
> >>>> Hi Sam/Sage,
> >>>>
> >>>> As we discussed earlier, enabling the present OpTracker code 
> >>>> degrading performance severely. For example, in my setup a single 
> >>>> OSD node with
> >>>> 10 clients is reaching ~103K read iops with io served from memory 
> >>>> while optracking is disabled but enabling optracker it is reduced to ~39K iops.
> >>>> Probably, running OSD without enabling OpTracker is not an option 
> >>>> for many of Ceph users.
> >>>>
> >>>> Now, by sharding the Optracker:: ops_in_flight_lock (thus xlist
> >>>> ops_in_flight) and removing some other bottlenecks I am able to 
> >>>> match the performance of OpTracking enabled OSD with OpTracking 
> >>>> disabled, but with the expense of ~1 extra cpu core.
> >>>>
> >>>> In this process I have also fixed the following tracker.
> >>>>
> >>>>
> >>>>
> >>>> http://tracker.ceph.com/issues/9384
> >>>>
> >>>>
> >>>>
> >>>> and probably http://tracker.ceph.com/issues/8885 too.
> >>>>
> >>>>
> >>>>
> >>>> I have created following pull request for the same. Please review it.
> >>>>
> >>>>
> >>>>
> >>>> https://github.com/ceph/ceph/pull/2440
> >>>>
> >>>>
> >>>>
> >>>> Thanks & Regards
> >>>>
> >>>> Somnath
> >>>>
> >>>>
> >>>>
> >>>>
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