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: > > On 12/26/15 21:51, Mark Millard wrote: >> Context: >> >>> # 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 >> >> >> 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). >> >> 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). >> >> I'm not sure it will be readable but the below is a capture of a systat -vmstat display. >> > > Hi, > > 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. > > You can disable USB like this: > > usbconfig -d 0.1 set_config 255 > > And the interrupts should go down to zero. > > Re-enable like this: > > usbconfig -d 0.1 set_config 0 > > --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=3, CS=20f10027 Dec 27 07:39:24 rpi2 kernel: bcm_dma0: unused DMA intr CH=3, CS=20f10027 Dec 27 07:41:02 rpi2 kernel: bcm_dma0: unused DMA intr CH=3, CS=20f10027 Dec 27 07:43:51 rpi2 kernel: bcm_dma0: unused DMA intr CH=3, CS=20f10027 (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]==1 status. clang++ is one of the programs getting Bus Errors. === Mark Millard markmi at dsl-only.nethome | help
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