On Mon, 2014-02-10 at 21:56 +0100, Thomas Glanzmann wrote: > Hello Nab, > > > This looks correct to me. Thomas, once your able to confirm please > > include your 'Tested-by' and I'll include for the next -rc3 PULL > > request. > > Eric is currently reviewing our latest iteration with MSG_MORE for > kernel_sendmsg and MSG_MORE | MSG_SENDPAGE_NOTLAST for sendpage. However > with the last iteration we had again a high RTT for some packets. But > than Eric let me tune net.ipv4.tcp_min_tso_segs to 8 and the RTT went > down to what it used before auto corking was enabled. At least almost. > Hmm.. I was not aware of high RTT for some packets. Can you spot this on the pcap you provided ? > I'm having a steep learning curve but Eric hopefully knows how to get > this back in check. Nevertheless the regression I saw are history > because I saw that Eric has submitted the patch to David S. Miller which > fixes the two bugs that killed the iSCSI performance when tcp auto > corking was on. So currently we're just optimizing to get the last 20% > or so out of it. Quite interesting. Especially how much bandwidth can be > saved by coalescing packets. It depends on the ratio payload/headers. The beginning of your pcap show a lot of 512 bytes requests, so for this kind of requests, the gain is huge (maybe 50%), but for 32K or 64K request, gain would be marginal. -- To unsubscribe from this list: send the line "unsubscribe target-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
