Date: Wed, 8 May 2013 20:44:41 +1000 From: Peter Jeremy <peter@rulingia.com> To: Adrian Chadd <adrian@freebsd.org> Cc: freebsd-arm@freebsd.org Subject: Re: Sawtooth ping RTT on RPi Message-ID: <20130508104441.GC90732@server.rulingia.com> In-Reply-To: <CAJ-VmomfoPCFs9=wzt8SzXY2K3MCY7owAR2thKTC2Sn0pP2_Vg@mail.gmail.com> References: <20130508085901.GA90732@server.rulingia.com> <CAJ-VmomK15L_Cx=pQDFv-pRu3SfT4aRXzsYX_Rp_si8NofMZ-Q@mail.gmail.com> <20130508095414.GB90732@server.rulingia.com> <CAJ-VmomfoPCFs9=wzt8SzXY2K3MCY7owAR2thKTC2Sn0pP2_Vg@mail.gmail.com>
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--i7F3eY7HS/tUJxUd Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2013-May-08 03:12:43 -0700, Adrian Chadd <adrian@freebsd.org> wrote: >yup, that looks like two almost-but-not-in-sync sampling periods (one >being poll, one being ping) beating against each other. That seems like a reasonable hypothesis. >Is the USB stuff being polled? I'm not sure. I don't think so. dmesg says: dwcotg0: <DWC OTG 2.0 integrated USB controller> mem 0x20980000-0x2099ffff = irq 17 on simplebus0 usbus0 on dwcotg0 smsc0: <vendor 0x0424 product 0xec00, rev 2.00/2.00, addr 3> on usbus0 ue0: <USB Ethernet> on smsc0 So there's an interrupt available and nothing else is using irq 17. And systat shows that the interrupt rate on irq 17 goes up with network traffic (though it idles at ~500 interrupts/sec - which seems excessive). --=20 Peter Jeremy --i7F3eY7HS/tUJxUd Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iEYEARECAAYFAlGKLJkACgkQ/opHv/APuIdq/ACgndhF1asSAun3k5USRo17lIw6 RLkAn0UfZ1QbaC4eAJXYViQuLRRhgcK+ =JVbO -----END PGP SIGNATURE----- --i7F3eY7HS/tUJxUd--
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