Date: Sun, 27 Dec 2015 15:04:13 -0800 From: Mark Millard <markmi@dsl-only.net> To: Hans Petter Selasky <hps@selasky.org> Cc: freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: fyi: 11.0-current rpi2 systat -vmstat shows around 24k interrupts for bcm283x_dw Message-ID: <2D9BD203-03D8-4354-A335-8C43A11D1BB3@dsl-only.net> In-Reply-To: <56806007.2000302@selasky.org> References: <0A781C7D-C5F5-4931-AE38-D2FEC0848DCA@dsl-only.net> <56806007.2000302@selasky.org>
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On 2015-Dec-27, at 2:02 PM, Hans Petter Selasky <hps@selasky.org> wrote: >=20 > On 12/26/15 21:51, Mark Millard wrote: >> Context: >>=20 >>> # freebsd-version -ku; uname -aKU >>> 11.0-CURRENT >>> 11.0-CURRENT >>> FreeBSD rpi2 11.0-CURRENT FreeBSD 11.0-CURRENT #2 r292413M: Fri Dec = 25 18:03:19 PST 2015 = root@FreeBSDx64:/usr/obj/clang/arm.armv6/usr/src/sys/RPI2-NODBG arm = 1100091 1100091 >>=20 >>=20 >> For a basically near-idle context systat -vmstat lists "Int" and 23k = to 25k normally (almost always 24k) and bcm283x_dw at the right shows = figures like 24118. "generic_ti" is more like 232 and "ipi 76" is more = like 111. The others at the right are normally blank (other than total). >>=20 >> Lots of bcm283x_dw interrupts if around 24k is correct. As the = numbers do not change scale when the systat refresh interval is = explicitly scaled, I assume that the figures are per second (or per some = other time unit, possibly just for the most recent unit instead of = mean). >>=20 >> I'm not sure it will be readable but the below is a capture of a = systat -vmstat display. >>=20 >=20 > Hi, >=20 > The dwc_otg needs to be served frequently in PIO mode. Your number is = expected. We're using fast interrupts for most of this work, so no = task-switching is involved and so the CPU consumption remains low. >=20 > You can disable USB like this: >=20 > usbconfig -d 0.1 set_config 255 >=20 > And the interrupts should go down to zero. >=20 > Re-enable like this: >=20 > usbconfig -d 0.1 set_config 0 >=20 > --HPS Good to know. Thanks. I'm unlikely to disable USB: I've not set up a = alternate serial connection. FYI (but probably unrelated?): I've not tracked anything down yet but I = do periodically get messages like: Dec 27 07:31:56 rpi2 kernel: bcm_dma0: unused DMA intr CH=3D3, = CS=3D20f10027 Dec 27 07:39:24 rpi2 kernel: bcm_dma0: unused DMA intr CH=3D3, = CS=3D20f10027 Dec 27 07:41:02 rpi2 kernel: bcm_dma0: unused DMA intr CH=3D3, = CS=3D20f10027 Dec 27 07:43:51 rpi2 kernel: bcm_dma0: unused DMA intr CH=3D3, = CS=3D20f10027 (But I also go long times without such.) Note: I'm currently involved in experiments providing evidence about Bus = Errors from software that misaligns pointer values and possibly from = inappropriate/insufficient compiler options for the SCTLR bit[1]=3D=3D1 = status. clang++ is one of the programs getting Bus Errors. =3D=3D=3D Mark Millard markmi at dsl-only.net
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