From: Krzysztof Halasa <khc@pm.waw.pl>
To: ddutile@redhat.com
Cc: Stefan Assmann <sassmann@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jesse Barnes <jbarnes@virtuousgeek.org>,
kaneshige.kenji@jp.fujitsu.com, matthew@wil.cx
Subject: Re: GT/s vs Gbps for PCIe bus speed
Date: Thu, 15 Oct 2009 19:58:49 +0200 [thread overview]
Message-ID: <m3y6nc1que.fsf@intrepid.localdomain> (raw)
In-Reply-To: <4AD655E1.7080005@redhat.com> (Don Dutile's message of "Wed, 14 Oct 2009 18:51:13 -0400")
Don Dutile <ddutile@redhat.com> writes:
>>> No matter how many lanes, or how the data is sent (long or short bursts),
>>> the frequency rate is a constant.
I'm not sure there is such thing as "frequency rate" (but English isn't
my first language). Rate, yes - symbol rate, clock rate (not used here),
code rate. Frequency is a clearly defined but different thing.
> Frequency changing would require link re-synch.
> This code is dealing w/steady-state frequency.
Believe me or not, there is no single frequency on PCIe link.
Google shows for example:
http://www.home.agilent.com/upload/cmc_upload/All/PCIe_HighSpeedSymposiumDec2008.pdf
See page 30, it's frequency spectrum for PCIe 3.0 but the idea is the
same. Also note consistent use of "GT/s" to avoid confusion.
> Again, trying to generate output that relates
> to what devices are spec to run at: 2.5GHz or 5.0GHz links.
That seems like wifi rather than PCIe.
--
Krzysztof Halasa
prev parent reply other threads:[~2009-10-15 17:59 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-14 8:42 GT/s vs Gbps for PCIe bus speed Stefan Assmann
2009-10-14 18:51 ` Krzysztof Halasa
2009-10-14 19:49 ` Don Dutile
2009-10-14 20:50 ` Roland Dreier
2009-10-15 7:32 ` Kenji Kaneshige
2009-10-14 21:33 ` Krzysztof Halasa
2009-10-14 22:51 ` Don Dutile
2009-10-15 7:40 ` Roland Dreier
2009-10-15 14:05 ` Don Dutile
2009-10-15 17:58 ` Krzysztof Halasa [this message]
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