On Thu, Dec 08, 2016 at 03:48:13PM +0100, Jesper Dangaard Brouer wrote: > On Thu, 8 Dec 2016 11:06:56 +0000 > Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> wrote: > > > On Thu, Dec 08, 2016 at 11:43:08AM +0100, Jesper Dangaard Brouer wrote: > > > > That's expected. In the initial sniff-test, I saw negligible packet loss. > > > > I'm waiting to see what the full set of network tests look like before > > > > doing any further adjustments. > > > > > > For netperf I will not recommend adjusting the global default > > > /proc/sys/net/core/rmem_default as netperf have means of adjusting this > > > value from the application (which were the options you setup too low > > > and just removed). I think you should keep this as the default for now > > > (unless Eric says something else), as this should cover most users. > > > > > > > Ok, the current state is that buffer sizes are only set for netperf > > UDP_STREAM and only when running over a real network. The values selected > > were specific to the network I had available so milage may vary. > > localhost is left at the defaults. > > Looks like you made a mistake when re-implementing using buffer sizes > for netperf. We appear to have a disconnect. This was reintroduced in response to your comment "For netperf I will not recommend adjusting the global default /proc/sys/net/core/rmem_default as netperf have means of adjusting this value from the application". My understanding was that netperfs means was the -s and -S switches for send and recv buffers so I reintroduced them and avoided altering [r|w]mem_default. Leaving the defaults resulted in some UDP packet loss on a 10GbE network so some upward adjustment. >From my perspective, either adjusting [r|w]mem_default or specifying -s -S works for the UDP_STREAM issue but using the switches meant only this is affected and other loads like sockperf and netpipe will need to be evaluated separately which I don't mind doing. > See patch below signature. > > Besides I think you misunderstood me, you can adjust: > sysctl net.core.rmem_max > sysctl net.core.wmem_max > > And you should if you plan to use/set 851968 as socket size for UDP > remote tests, else you will be limited to the "max" values (212992 well > actually 425984 2x default value, for reasons I cannot remember) > The intent is to use the larger values to avoid packet loss on UDP_STREAM. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>