Messages in this thread | | | Date | Wed, 8 May 2013 14:14:44 -0400 | From | Chris Metcalf <> | Subject | Re: [GIT PULL, RFC] Full dynticks, CONFIG_NO_HZ_FULL feature |
| |
On 5/6/2013 3:32 PM, Linus Torvalds wrote: > On Mon, May 6, 2013 at 8:35 AM, Paul E. McKenney > <paulmck@linux.vnet.ibm.com> wrote: >>> >>> I think Linus might have referred to my 'future plans' entry: > > Indeed. I feel that HPC is entirely irrelevant to anybody, > *especially* HPC benchmarks. In real life, even HPC doesn't tend to > have the nice behavior their much-touted benchmarks have. > > So as long as the NOHZ is for HPC-style loads, then quite frankly, I > don't feel it is worth it. The _only_ thing that makes it worth it is > that "future plans" part where it would actually help real loads.
The work is very relevant to a lot of the actual customer applications that Tilera chips are sold into: running very low latency userspace applications that handle packet processing (or, to a lesser extent, video frame processing). For packet processing in particular, you really want to be able to guarantee that you can set up a core handling packets in userspace and get NO INTERRUPTS at all, ever. If you do get an interrupt, you end up dropping a bunch of packets on the floor.
We are still using code I developed internally for this (for the curious, in my dataplane branch on kernel.org), but I expect in the relatively near future we will be trying to switch to the NOHZ stuff instead. I'm really pleased to see it start getting merged up. -- Chris Metcalf, Tilera Corp. http://www.tilera.com
| |