Messages in this thread | | | Date | Mon, 15 Dec 2008 08:02:47 -0600 (CST) | From | Christoph Lameter <> | Subject | Re: [rfc][patch] SLQB slab allocator |
| |
On Mon, 15 Dec 2008, Nick Piggin wrote:
> > Does this mean that SLQB is less efficient than SLUB for off node > > allocations? SLUB can do off node allocations from the per cpu objects. It > > does not need to make the distinction for allocation. > > I haven't measured them, but that could be the case. However I haven't > found a workload that does a lot of off-node allocations (short lived > allocations are better on-node, and long lived ones are not going to > be so numerous).
A memoryless node is a case where all allocations will be like that.
> That's more complexity, though. Given that objects are often hot when > they are freed, and need to be touched after they are allocated anyway, > the simple queue seems to be reasonable.
Yup.
> This case does improve the database score by around 1.5-2%, yes. I > don't know what you mean exactly, though. What case, and what do you > mean by bad cache unfriendly programming? I would be very interested > in improving that benchmark of course, but I don't know what you > suggest by keeping cachelines hot in the right way?
What I was told about the database test is that it collects lists of objects from various processors that are then freed on a different processor. This means all objects are cache cold.
| |