On Wed, Feb 3, 2016 at 3:57 PM, Matt Benjamin <mbenjamin@xxxxxxxxxx> wrote: > > Hi, > > I think we should go with small_vector for this role, yes. I found two issues. First, there are critical defects in small_vector prior to boost 1.6.0. Second, though it is header-only, the coupling with related version-specific boost types (container, allocator, respective detail types, and platform-specific selectors...) seems to make pulling it in separately pretty unrealistic as an option. I looked at the cost of pulling in and selectively compiling (libs) an entire boost 1.6, and that went a lot easier (added less than a minute to my build time). > > Matt > > ----- Original Message ----- > > From: "Sage Weil" <sweil@xxxxxxxxxx> > > To: "Allen Samuels" <Allen.Samuels@xxxxxxxxxxx> > > Cc: ceph-devel@xxxxxxxxxxxxxxx, mbenjami@xxxxxxxxxx, cbodley@xxxxxxxxxx > > Sent: Wednesday, February 3, 2016 3:04:57 PM > > Subject: Re: inline vector container > > > > On Wed, 3 Feb 2016, Allen Samuels wrote: > > > One thing that the code base needs is a simple vector container that is > > > optimized for a small number of elements, i.e., for small element counts we > > > avoid the malloc/free overhead. But fully supports being resized into > > > larger > > > containers that are unbounded. Of course it will need to follow all of the > > > proper object copy/move semantics so that things like unique_ptr, etc work > > > correctly. > > > > > > I heard rumors that there was one available in the boost world, but I can’t > > > seem to find it. Do you know about one being available? > > > > http://www.boost.org/doc/libs/1_60_0/doc/html/boost/container/small_vector.html The fb / folly code also has a small vector: https://github.com/facebook/folly/blob/master/folly/small_vector.h that used a C++11 move semantics whenever possible. Compared other parts of folly this has pretty small dependencies on folly and those can prob be ripped out. > > > > > > > I’ve been prototyping one myself, just to get re-familiar with all of the > > > C++11 move sementics, and trivial constructors, etc. > > > > > > The code is pretty complete, but the testing gets rather involved. There’s > > > no reason to contain this if it’s available elsewhere. But if it isn’t I > > > plan on continuing this… > > > > I think Casey had prototyped something similar using a custom allocator, > > too, but I didn't actually look at the result. And Matt talked about just > > pulling the boost one in-tree until we get updated boost in the supported > > distros, but I forget if he ran into problems there or not... > > > > sage > > -- > -- > Matt Benjamin > Red Hat, Inc. > 315 West Huron Street, Suite 140A > Ann Arbor, Michigan 48103 > > http://www.redhat.com/en/technologies/storage > > tel. 734-707-0660 > fax. 734-769-8938 > cel. 734-216-5309 > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Milosz Tanski CTO 16 East 34th Street, 15th floor New York, NY 10016 p: 646-253-9055 e: milosz@xxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
