From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 In-Reply-To: References: <87C61423-7C13-4516-88B5-C2ABA7D32AA9@me.com> Date: Wed, 6 May 2015 23:28:52 +0100 Message-ID: From: Charles Forsyth To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Content-Type: multipart/alternative; boundary=047d7bb04b0ee2918005157151f0 Subject: Re: [9fans] fossil+venti performance question Topicbox-Message-UUID: 4fe219aa-ead9-11e9-9d60-3106f5b1d025 --047d7bb04b0ee2918005157151f0 Content-Type: text/plain; charset=UTF-8 On 6 May 2015 at 22:28, David du Colombier <0intro@gmail.com> wrote: > Since the problem only happen when Fossil or vacfs are running > on the same machine as Venti, I suppose this is somewhat related > to how TCP behaves with the loopback. > Interesting. That would explain the clock-like delays. Possibly it's nearly zero RTT in initial exchanges and then when venti has to do some work, things time out. You'd think it would only lead to needless retransmissions not increased latency but perhaps some calculation doesn't work properly with tiny values, causing one side to back off incorrectly. --047d7bb04b0ee2918005157151f0 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

= On 6 May 2015 at 22:28, David du Colombier <0intro@gmail.com>= wrote:
Since the problem only happen when Fossil or vacfs = are running
on the same machine as Venti, I suppose this is somewhat related
to how TCP behaves with the loopback.
=C2=A0
Interesting. That would explain the clock-like delays.
Possibly it's nearly zero RTT in initial exchanges and= then when venti has to do some work,
thing= s time out. You'd think it would only lead to needless retransmissions = not increased latency
but perhaps some calc= ulation doesn't work properly with tiny values, causing one side to bac= k off
incorrectly.
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