| Title: | DIGITAL UNIX (FORMERLY KNOWN AS DEC OSF/1) |
| Notice: | Welcome to the Digital UNIX Conference |
| Moderator: | SMURF::DENHAM |
| Created: | Thu Mar 16 1995 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 10068 |
| Total number of notes: | 35879 |
We have 2 systems that have fast, full duplex ethernet. Every once in a
while, we get the following message in the messages file (tu2 is the
ethernet card):
tu2: transmit FIFO underflow: threshold raised to: 512 bytes
What is this telling me, and should we be concerned?
Thanks,
/jim
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 9150.1 | netrix.lkg.dec.com::thomas | The Code Warrior | Thu Mar 13 1997 08:45 | 2 | |
The card couldn't DMA data fast enough to transmit a packet so it raised it's threshold up a notch. Nothing to be concerned about. | |||||
| 9150.2 | It can't create small packets fast enough?? | DYOSW5::WILDER | Does virtual reality get swapped? | Thu Mar 13 1997 18:24 | 11 |
>>The card couldn't DMA data fast enough to transmit a packet so it
>>raised it's threshold up a notch. Nothing to be concerned about.
You mean that it can't DMA fast enough to create a packet to send so it
starts creating a bigger packet? Is this what the "threshold" means? (I
recently saw it go to 256, then 512 after a reboot).
Thanks,
/jim
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| 9150.3 | No problem. | SMURF::GILLUM | Kirt Gillum | Fri Mar 14 1997 12:11 | 13 |
No, I suppose it's our own fault for even printing such messages.
The chip has an onboard FIFO, and that's the buffer that's used between
host memory and the "wire"... When you see that message (I see it all
the time as soon as I start pounding the driver), it simply means that
the system can't deliver data to the Tulip chip fast enough to keep the
current FIFO full. Setting the threshold larger allows the chip to get
more of the packet before it starts sending (therefore, hopefully,
allowing the system to get a head start on the DMA).
I routinely get the threshold size up to 1024. Don't worry about it.
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| 9150.4 | Thanks | DYOSW5::WILDER | Does virtual reality get swapped? | Fri Mar 14 1997 12:23 | 2 |
Thanks!
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