Re: i486 can't keep up with 2.2.12 ?
Nicholas R LeRoy (nick.leroy@norland.com)
Thu, 14 Oct 1999 09:12:56 -0500
> On Wed, 13 Oct 1999, Frank v Waveren wrote:
>
> > On Wed, Oct 13, 1999 at 08:48:01AM -0400, tenthumbs wrote:
> > > I have an old i486 machine with a not quite so old Cyrix 5x86 cpu and
> > > four IDE drives. (I have unmasked irq's on all drives so that's not an
> > > issue.) Using a 2.2.12 kernel and pppd 2.3.9, there are a fairly large
> > > number of packet errors. With just virtual consoles (no X) and just one
> > > user program (fetchmail) running, ifconfig shows this:
> > >
> > > ppp0 Link encap:Point-to-Point Protocol
> > > UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1
> > > RX packets:4301 errors:12 dropped:0 overruns:0 frame:12 <---
> > > TX packets:4213 errors:0 dropped:0 overruns:0 carrier:0
> > > collisions:0 txqueuelen:
> > >
> > > Over a longer period of 64 minutes, ifconfig reported more frame errors
> > > and "netstat -s" showed
> > >
> > > TcpExt:
> > > 105 packets pruned from receive queue because of socket buffer
> > > overrun
> > >
> > > which doesn't seem good.
> > >
> > >
> > > None of this happens with a 2.0.38 kernel and pppd 2.2.0f.
> > >
> > > I can see that this might be due to a change in the disk code or in the
> > > network code or in pppd. Does anyone have any ideas?
> > >
> > > Thanks.
> >
> > Have you tried setting the config option Cpu can't handle full bandwith?
>
> My old 386 dx/40 could handle alot more than one puny little ppp
> connection.
>
> Stephen
>
Jumping into the middle of the discussion -- I'm sure that one of you
has thought of this already, but, just to make sure:
Is this running on a 16550 type UART or a 16450? The 16450 will almost
certainly lose characters running at those speeds. No FIFO, just doesn't
leave the CPU enough time to read the data out between interrupts.
Just my $.02 worth...
-Nick
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