Thanks to all for the attention. I like the idea of testing for newly modified
files on the SD flash. I think I've disabled all writes, but it is difficult to
know that I've been thorough enough. As far as I know, SD flash is the only
writable flash on the 7350.
My problem differs from the one on the thread about serial IO dropping
characters, as my (console) serial port does not drop characters, but merely
delays echoing (hard to say whether the delay is in the receiving part, or the
sending part, or both). Neither does my CANbus seem to drop packets.
I do remember one or more threads about SD flash writes disrupting things, and
I'm sure that the one pointed out in this thread is one of them. I cannot seem
to find the others, so if anyone else has found them, I'd like to re-read those.
Keep the ideas coming folks. Thanks again
--- rod.
--- In Larry <> wrote:
>
> This is a problem I see reported often. I scratched my head on this for
> awhile before figuring it out.
> It is most likely a flash update taking place. It appears that
> interrupts must be getting turned off
> during the erase and/or write cycle. On boards that use external flash
> like CF or SD cards you
> don't seem to see this, however, on cards with solder down flash it does
> seem to happen.
>
> Even if you are not changing any files intentionally, there is likely
> logging going on from one or
> more daemons. Apache has a log for instance. There is also syslog.
> To fix this you can turn off logging, reroute logging to /dev/null or
> reroute to RAM.
>
> Another way is to map a ramdisk partition and create a link from the
> flash directory into the
> ramdisk partition.
>
> How I managed to track down the culprits was to use the find
> <http://linux.die.net/man/1/find>command
> You can specify date stamp newer than x so you can determine what files
> were written.
> From there you have to eliminate the cause.
>
> Good luck!
> Larry
>
> On 12/6/2012 4:10 PM, Rod wrote:
> >
> > Les, thanks for your response. I forgot to mention that I also see
> > this periodically at the shell prompt, where no characters are echoed
> > for a few seconds while typing. The characters are not lost, simply
> > delayed in being echoed.
> >
> > This is becoming a significant concern.
> >
> > --- rod.
> >
> > --- In <ts-7000%40yahoogroups.com>,
> > "aeroelastic" <aeroelastic@> wrote:
> > >
> > > I see this as well, and am not using the CAN bus. I have killed most
> > of the daemons running, apache, inetd, etc. still the pauses continue,
> > and top does not reveal any culprit.
> > >
> > > It DOES sometimes seem like it is on the console or terminal (ssh)
> > that the problem is the worst. Running application seem less prone to
> > the dead spots.
> > >
> > > I have tried playing with the nice settings, but the problem
> > persists on terminal and ssh
> > >
> > > Les
> > >
> > > --- In <ts-7000%40yahoogroups.com>,
> > "Rod" <bomr@> wrote:
> > > >
> > > > I am seeing problems of applications running on a TS-7350 that go
> > 'dead' (for lack of a better description) for periods of 2-5 seconds.
> > This seems to happen irregularly, but generally every 1 to 10 minutes.
> > I suspect that there is some daemon process running periodically that
> > is hogging all userspace CPU, since running 'top' doesn't show
> > anything, but does also appear to go dead for brief periods (although
> > this is very difficult to assess for sure).
> > > >
> > > > I've turned off swapping, and have tried to eliminate anything
> > else I thought was unnecessary for my application. There are no cron
> > jobs running. Can anyone suggest where else to look?
> > > >
> > > > I'm using a default 2.6.21 kernel, and am also using the TS-CAN1
> > CANbus interface with the TS supplied driver. I suspect that the
> > problem exists even without the CANbus, but the CANbus interface
> > allows me to see the problem, as I am grabbing time-stamped messages
> > from the bus, and I know those timestamps are accurate.
> > > >
> > > > Thanks.
> > > >
> > > > --- rod.
> > > >
> > >
> >
> >
>
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