revolutions per minute - a new metric for measuring responsiveness
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From: "Toke Høiland-Jørgensen" <toke@toke.dk>
To: Omer Shapira <omer_shapira@apple.com>,
	Christoph Paasch <cpaasch@apple.com>,
	Rich Brown <richb.hanover@gmail.com>
Cc: Rpm <rpm@lists.bufferbloat.net>
Subject: Re: [Rpm] Does RPM measurement *require* a valid SSL certificate
Date: Thu, 21 Oct 2021 13:45:58 +0200	[thread overview]
Message-ID: <87y26md2ix.fsf@toke.dk> (raw)
In-Reply-To: <4C9625A0-6276-4073-A43F-A57C22F268C6@apple.com>

Omer Shapira via Rpm <rpm@lists.bufferbloat.net> writes:

> 2. The notion that “it’s easy enough to stand up code to respond to
> HTTP” - this may be true, but the role of the server is not to just
> respond, it will have to actually saturate the link. This requires
> sufficient processing power to send the data at the required rate.
> Hence, the boxes that rely on a SOC to move the bytes, and have low
> power master CPU may not be able to saturate the link.

I'll add another complication to this, at least for Linux: TCP Small
Queues (TSQ). If the server responding to the requests is the AP, TSQ
can do a quite good job of keeping those streams from saturating the
queues of the WiFi interface, meaning you won't expose any bloat that
may be hiding there. This varies between implementations, but it's quite
possible to have an AP that has no bufferbloat when running a test
against a server on the AP itself, but is severely bloated when
forwarding packets.

-Toke

      reply	other threads:[~2021-10-21 11:46 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-13 19:18 Rich Brown
2021-10-13 19:45 ` Randall Meyer
2021-10-13 21:57   ` Rich Brown
2021-10-14 20:27     ` Christoph Paasch
2021-10-15 15:10       ` Rich Brown
2021-10-15 16:38         ` Toke Høiland-Jørgensen
2021-10-15 17:19           ` Rich Brown
2021-10-15 16:38         ` Jonathan Foulkes
2021-10-20 18:30         ` Christoph Paasch
2021-10-20 18:47           ` Rich Brown
2021-10-20 23:04           ` Omer Shapira
2021-10-21 11:45             ` Toke Høiland-Jørgensen [this message]

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