Date: Tue, 17 Sep 2013 19:32:56 +0200 From: Harald Schmalzbauer <h.schmalzbauer@omnilan.de> To: Ian Lepore <ian@FreeBSD.org> Cc: lev@FreeBSD.org, FreeBSD Stable <freebsd-stable@FreeBSD.org>, freebsd-usb@FreeBSD.org, Hans Petter Selasky <hans.petter.selasky@bitfrost.no> Subject: Re: umcs (4-Port-USB-serial) triggering way too much ehci IRQs Message-ID: <52389248.7080109@omnilan.de> In-Reply-To: <1379434567.1197.48.camel@revolution.hippie.lan> References: <52372DBA.6020703@omnilan.de> <zarafa.5237e529.2bc6.08fde6eb34c27a87@mail.lockless.no> <875323075.20130917124437@serebryakov.spb.ru> <523816E1.10603@omnilan.de> <1857258551.20130917124737@serebryakov.spb.ru> <5238198C.3070604@bitfrost.no> <52381BAC.5010801@omnilan.de> <52381FCA.5030509@bitfrost.no> <5238775C.8010000@omnilan.de> <1379434567.1197.48.camel@revolution.hippie.lan>
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This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig38A906B84D5930E472AEDBEC Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Bez=FCglich Ian Lepore's Nachricht vom 17.09.2013 18:16 (localtime): > On Tue, 2013-09-17 at 17:38 +0200, Harald Schmalzbauer wrote: >> ... >>> Try this patch and see what happens: >>> >>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D >>> --- umcs.c (revision 255492) >>> +++ umcs.c (local) >>> @@ -230,6 +230,7 @@ >>> .bufsize =3D 0, /* use wMaxPacketSize */ >>> .callback =3D &umcs7840_intr_callback, >>> .if_index =3D 0, >>> + .interval =3D 20, /* ms */ >>> }, >>> }; >>> >>> >>> BTW: I see that the umcs driver shouldn't do synchronous control >>> transfers from the USB interrupt transfer callback. This should be >>> postponed into some worker thread, for example the USB explore thread= =2E >>> See USB audio driver for an example. >>> >>> --HPS >> I tried your patch and it works as expected: IRQs decreased to ~64/s >> when idle/disconnected. >> >> One interesting thing I never measured before: >> Console connection with 115k2 via umcs and 'while ( 2>1 ) echo "---...= " >> end' results in 8000 irqs/s :-( But that's also true for the prolific >> (uplcom). The latter just goes down to 0.0 irqs/s when idle. >> >> Doing the same with uart0 results in 1444irqs/s. >> Is it by design/unavoidable that transfering the same via USB multipli= es >> by factor 5-6? >> >> Thanks, >> >> -Harry >> > I don't know about that chipset, but with the FTDI chips it does xfers > in 64 byte chunks and high speed bulk data results in an astronomical > number of interrupts (and if you go fast enough, lost data). I have According to ASIX product brief, MCS7840 has 512 byte buffer. Pretty much for an UART I think, which should make 115k2 baud connections with less than 30 transfers/s work, or am I missing something? > some patches that assemble lots of the little chip-size buffers into > bigger xfers that the ohci/ehci controller can handle without > interrupting the processor; that helps the problem a bunch. I think I also have at least one FTDI adapter arround, so I'd happily testing if I can make it compile on RELENG_9_2. Thanks, -Harry --------------enig38A906B84D5930E472AEDBEC Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (FreeBSD) iEYEARECAAYFAlI4kkgACgkQLDqVQ9VXb8iibACgiAipzBpCR/Q7LgKUwfIav0As 5lAAoJ7gNVddRt7cyVnBa9FKorIzz4xB =q662 -----END PGP SIGNATURE----- --------------enig38A906B84D5930E472AEDBEC--
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