Date: Sat, 1 May 2004 20:08:27 +1000 (EST) From: Bruce Evans <bde@zeta.org.au> To: Burkard Meyendriesch <bm@malepartus.de> Cc: freebsd-current@FreeBSD.org Subject: Re: sio: lots of silo overflows on Asus K8V with Moxa Smartio C104H/PCI Message-ID: <20040501194658.I20349@gamplex.bde.org> In-Reply-To: <20040501094332.49356c55.bm@malepartus.de> References: <20040426111754.38a855c4.bm@malepartus.de> <20040426233925.Y5300@gamplex.bde.org> <20040501140658.F19558@gamplex.bde.org> <20040501094332.49356c55.bm@malepartus.de>
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On Sat, 1 May 2004, Burkard Meyendriesch wrote: > On Sat, 1 May 2004 14:23:13 +1000 (EST) Bruce Evans wrote: > > ... > > locking. Try the following patch if you still have shared interrupts: > > ... > > I don't expect this to fix your problem. > > Thank you for the patch! I just installed it in a new kernel. Result: > > /var/log/messages after boot -v: > .. > May 1 09:07:31 Reineke kernel: puc0: <Moxa Technologies, Smartio C104H/PCI> port 0xa000-0xa00f,0xa400-0xa43f,0xa800-0xa87f irq 19 at device 14.0 on pci0 > May 1 09:07:31 Reineke kernel: puc0: Reserved 0x40 bytes for rid 0x18 type 4 at 0xa400 > May 1 09:07:31 Reineke kernel: sio4: <Moxa Technologies, Smartio C104H/PCI> on puc0 > May 1 09:07:31 Reineke kernel: sio4: type 16550A > May 1 09:07:31 Reineke kernel: sio4: unable to activate interrupt in fast mode - using normal mode > .. Keep trying to make it use a fast interrupt. Most likely you need PUC_FASTINTR. > My Hardware is an Asus K8V Athlon64 board; in my BIOS I enabled "ACPI 2.0" > and "ACPI APIC". > > > > 19200 bps = 1920 cps = at least 1920/16 = 120 interrupts/second > > > > Here 16 is the input fifo size for the usual case of a 16550A UART. > > Use systat -v to see the transient interrupt rate. > > > At 115200 bps my puc interrupt rate is at about 300 ints/s, but I see > peeks up to 1500 ints/s. iostat 10 gives me an average char input rate > of 2300 chars/s. The silo overflow rate is about 1 per 5 seconds. It could still be an interrupt storm. I didn't noticed that you had hz = 1024. This gives about 102 interrupts/second from correct, but the storm handling isn't quite right and can permit more interrupts than intended. Another reson to try using a fast interrupt is that interrupt storm protection doesn't apply to them, so they should make the problem obvious by hanging the system :-). > At 9600 bps the puc interrupt rate is about 105 ints/s with 730 char/s > input character rate. At this low speed I don't see any silo overflows. 105 interrupts/second looks very like storm handling. The normal interrupt rate for 9600 bps input sustained is 960/14 = 68.6, and 9600 bps sustained should give 960 cps. Output increases the interrupt rate a little but should affect input speed. > Btw, systat -v shows a constant high interrupt rate of 1024 0: clk; > is this normal? 1024 is normal for amd64 only. "0: clk" is normal misformatting. RELENG_4 has the correct formatting "clk irq0". Bruce
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