| Title: | FDDI - The Next Generation |
| Moderator: | NETCAD::STEFANI |
| Created: | Thu Apr 27 1989 |
| Last Modified: | Thu Jun 05 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 2259 |
| Total number of notes: | 8590 |
Folks,
I'm looking for suggestions that I can use to increase the
performance of the FDDI controller or some type of an approach to
tuning the network in spite of its ongoing traffic. We have a
VAXcluster of 6 7620's and all have the DEMFA option.
The cluster is still running VMS 5.5-2 and may stay there for some
time, but if going to a version 6.x has some impact on this please
mention it also. My concerns are around sysgen parameters and how they
affect the network.
If you have a pointer to a white paper or something like it, please
mention it.
regards,
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 1931.1 | lrpsize, NISCS_MAX_PKTSZ. | 49393::HOTZ | gimme an F !!!, ...D !!!, ...D !!!, ...I !!!, what's that spell !!!? | Wed Jan 31 1996 10:28 | 44 |
SYSGEN Parameter LRPSIZE Must Be Increased for FDDI Equipped VAX Systems
PROBLEM:
There is a high probability that VAX systems running VMS Version 5.4-3
through 5.5-2H4 and equipped with an FDDI adapter(s) are running with
an incorrect LRPSIZE parameter value. The result is receive buffers
are allocated from a general pool rather than from the LRP lookaside
list, which results in a degradation of system performance.
If the LRPSIZE parameter value is not large enough for the data
structures holding the incoming messages, the buffers in the data link
driver's receive ring will be carved out of a nonpaged pool rather
than LRPs. Allocation from a nonpaged pool is much more expensive than
from the LRP lookaside list, and the nonpaged pool allocation is done
at IPL 11 while the data link drivers do most of their work at IPL 8.
The release notes for VMS 5.4-3 specify a value for the LRPSIZE
parameter of 4474 for VAX systems equipped with an FDDI. This value
must be increased by 131 (4605) for VMS Version 5.4-3 and 67 (4541)
for VMS Versions 5.5 thru 5.5-2H4. This is ONLY required for FDDI
equipped VAX systems running VMS Versions 5.4-3 through 5.5-2H4.
RESOLUTION:
All FDDI equipped VAX systems running VMS Version 5.4-3 should have
the LRPSIZE parameter set to a minimum of 4605. All FDDI equipped VAX
systems running VMS Versions 5.5 through 5.5-2H4 should have the
LRPSIZE parameter set to a minimum of 4541. This SYSGEN parameter
change requires that the system be rebooted.
ADDITIONAL COMMENTS:
This adjustment may require an increase in LRPCOUNT as more LRPs will
be consumed. This can be determined by monitoring the LRP lookaside
list using the SHOW MEMORY/POOL/FULL command.
Autogen should be run with the feedback option if the current size for
the LRP lookaside list has increased beyond the initial size.
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for VMS 6.*: use NISCS_MAX_PKTSZ, see the release notes.
greg.
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