Date: Fri, 8 Sep 2017 01:04:00 +1000 From: Paul Koch <paul.koch@akips.com> To: Sepherosa Ziehau <sephe@freebsd.org> Cc: Julian Elischer <julian@freebsd.org>, freebsd-stable@freebsd.org, Hongjiang Zhang <honzhan@microsoft.com> Subject: Re: 11.1 running on HyperV hn interface hangs Message-ID: <20170908010400.0fb81bc4@akips.com> In-Reply-To: <CAMOc5cx-dES8ABM8oNNKfT50ZUebVtpkKJn9Vtc_nQrRQ2vHgQ@mail.gmail.com> References: <20170906193309.796c79ed@akips.com> <3f96c7d0-4fbd-26cb-5c84-8868d12eb427@ingresso.co.uk> <14997bba-aac2-947b-9b78-04af41ea29b0@freebsd.org> <CAMOc5cxQp1P3WnDf=Hgo8X0LmQfjCTowO=ya8VsWhu4cdTeajQ@mail.gmail.com> <20170907150711.025e4e41@akips.com> <CAMOc5cx-dES8ABM8oNNKfT50ZUebVtpkKJn9Vtc_nQrRQ2vHgQ@mail.gmail.com>
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On Thu, 7 Sep 2017 13:51:11 +0800 Sepherosa Ziehau <sephe@freebsd.org> wrote: > Weird, your traffic pattern does not even belong to anything heavy. > Sending is mainly UDP, which will never be able to saturate the TX > buffer ring causing the RXBUF ACK sending failure. This is weird. It's a bit tricky. The poller is very fast. We ping every device every 15 seconds, and collect every MIB object every 60 seconds. The poller "rate limits" itself by dividing each minute into 100ms time slots and only sends a specific amount of pings/snmp packets in each time slot. The problem is, it blasts the request packets out really fast at the start of each time slot, and then sits in a receive loop until the next time slot comes around. The requests are not paced over the 100ms, therefore it will blast out a lot of packets in a few milliseconds. We use to use a 1 second rate limiting time slot, and didn't interlace ping/snmp requests, but we found certain interface types on Cisco 6509 switches couldn't keep up with back-to-back pings and would lose them. > Anyhow, make sure to test this patch: > 8762017-Sep-07 02:19 hn_inc_txbr.diff Yep. Might take a bit of time to test though because we'll need to get the customer to spin up a test VM on the same platform, and they are fairly remote (Perth, Australia). We don't run any Microsoft servers/HyperV setups in our lab. Paul. -- Paul Koch | Founder | CEO AKIPS Network Monitor | akips.com Brisbane, Australia
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