From: Pete Heist <pete@heistp.net>
To: Dave Taht <dave.taht@gmail.com>
Cc: Cake List <cake@lists.bufferbloat.net>
Subject: Re: [Cake] lockup with cake and veth
Date: Sat, 7 Jul 2018 00:12:53 +0200 [thread overview]
Message-ID: <8F1AFA8F-1799-49AD-AE48-A0BD1B22CFB8@heistp.net> (raw)
In-Reply-To: <CAA93jw6urUxpbOfNUKdyKYEr-V78ANXtEW5Q8v9Q+dUdZ6WS6Q@mail.gmail.com>
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Ok, it ended up being partly that, and mainly needing to increase kernel params for max TCP window memory, otherwise there was a hard limit on what I’d actually end up getting for the TCP window.
Rates start getting finicky with these large TCP windows, go too large and the rates can collapse for some reason, but I have managed to run about 6Gbit with 100ms RTT through Cake this way without a problem, either with a single stream or the aggregate of up to four streams. Or 20Gbit at 20ms RTT.
./qenv.sh on
./run_iperf.sh
./run_flent.sh
> On Jul 6, 2018, at 9:40 PM, Dave Taht <dave.taht@gmail.com> wrote:
>
> You ran out of queue to store for that rtt.
>
> netem limit 100000 or higher for that.
> On Fri, Jul 6, 2018 at 12:25 PM Pete Heist <pete@heistp.net> wrote:
>>
>> Only, I wonder if high BDP links can be emulated with netem. Say I want 10gbit with 100ms rtt. If I use “netem delay 50ms” each direction, rtt is correct, but throughput for iperf3 drops from 30Gbit to 450Mbit. CPU is a few percent, so that’s not the issue. Fiddling with TCP window (iperf3 -w) just seems to make it worse. So I’m still figuring out netem, I guess...
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prev parent reply other threads:[~2018-07-06 22:12 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-06 13:17 Pete Heist
2018-07-06 13:29 ` Toke Høiland-Jørgensen
2018-07-06 13:34 ` Georgios Amanakis
2018-07-06 13:37 ` Pete Heist
2018-07-06 19:24 ` Pete Heist
2018-07-06 19:40 ` Dave Taht
2018-07-06 22:12 ` Pete Heist [this message]
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