On Fri, Jan 6, 2017 at 8:52 AM, Kevin Grittner <kgri...@gmail.com> wrote:
> On Thu, Jan 5, 2017 at 7:32 PM, Jonathon Nelson <jdnel...@dyn.com> wrote: > > On Thu, Jan 5, 2017 at 1:01 PM, Andres Freund <and...@anarazel.de> > wrote: > >> On 2017-01-05 12:55:44 -0600, Jonathon Nelson wrote: > > >>> In our lab environment and with a 16MiB setting, we saw substantially > >>> better network utilization (almost 2x!), primarily over high bandwidth > >>> delay product links. > >> > >> That's a bit odd - shouldn't the OS network stack take care of this in > >> both cases? I mean either is too big for TCP packets (including jumbo > >> frames). What type of OS and network is involved here? > > > > In our test lab, we make use of multiple flavors of Linux. No jumbo > frames. > > We simulated anything from 0 to 160ms RTT (with varying degrees of > jitter, > > packet loss, etc.) using tc. Even with everything fairly clean, at 80ms > RTT > > there was a 2x improvement in performance. > > Is there compression and/or encryption being performed by the > network layers? My experience with both is that they run faster on > bigger chunks of data, and that might happen before the data is > broken into packets. > There is no compression or encryption. The testing was with and without various forms of hardware offload, etc. but otherwise there is no magic up these sleeves. -- Jon Nelson Dyn / Principal Software Engineer
