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Re: Non-paged dynamic memory

 
Wim Van den Wyngaert
Honored Contributor

Non-paged dynamic memory

I have about 60 AlphaStations with the same hardware and software. Only the name and address are different (VMS 7.2).

58 stations consume 2.5 MB np dyn mem. 2 consume 6.5 MB. This while using the same programs.

I checked with sda show pool/sum.

I found following big differences.
1) ORB normally takes 25 K but takes about 1 MB on the 2 stations
2) UCB normally takes 85 K but takes almost 2 MB on the 2 stations
3) MISC normally takes 100 K but takes 1.5 MB on the 2 stations

What does it all means and how can I find the process causing it ?

A virtual Duvel for he who solves it.

Wim
Wim
26 REPLIES 26
Wim Van den Wyngaert
Honored Contributor

Re: Non-paged dynamic memory

The Duvel is for me !

I found that BYTLM had been eaten too for certain processes. Then I found that 85% of available channels of that process were taken. Network problems caused the application to re-connect but without releasing the network devices.

Wim
Wim
Volker Halle
Honored Contributor

Re: Non-paged dynamic memory

Wim,

let's start looking at the UCBs (these should be Unit Control Blocks for devices).

SDA> SHOW POOL/HEAD/TYPE=UCB

type return until the list ends. It should tell you the UCB packet count and the bytes used for all those UCBs.

Then look at some of the UCB addresses found with SDA> SHOW DEV/ADDR= - take some addresses from the end of the UCB packet list.

Which kind of devices are these ?

Then do the same with /TYPE=ORB. ORBs are Object's Rights Blocks. What's the no. of packets ? You can format some of the ORBs with

SDA> READ SYSDEF
SDA> FORMAT

The associated device name is pointed to by
ORB$L_NAME_POINTER, so after you formatted an ORB, try:

SDA> EXAM @(.+orb$l_name_pointer);8

If the count of UCBs, ORBs and MISCs is about the same, you'll known that these packets somehow all are related to each other.

Volker.

PS: My guess would be: something from TCPIP, but you'll find out soon...
Wim Van den Wyngaert
Honored Contributor

Re: Non-paged dynamic memory

Volker,

Show dev net/fu shows a lot of devices allocated by a few processes. But in TCPIP there is no device and in decnet no connection. What could be the problem ?

The application people don't know why.

Wim
(half the Duvel is for you)
Wim
Volker Halle
Honored Contributor

Re: Non-paged dynamic memory

Wim,

so the UCBs/ORBs/MISCs are for which devices - TCPIP or DECnet ?

Volker.
Wim Van den Wyngaert
Honored Contributor

Re: Non-paged dynamic memory

The evidence is already gone (had to reset the stations). But it was decnet+. The proceses connect to processes on server node. If that fails, they retry in a loop.

But my main question is : why is the net device not deallocated ? Bug in decnet (7.3 eco 3) ?

Wim
Wim
Volker Halle
Honored Contributor

Re: Non-paged dynamic memory

Wim,

how are you going to ever document, analyze and find errors, if you 'delete the evidence' ? A forced crash would have provided the same results (after the reboot), but would have captured all the info needed...

If we assume those were NETn: devices, may there is a $DASSGN missing ?

Volker.
Ian Miller.
Honored Contributor

Re: Non-paged dynamic memory

The MISC could be buffers for the buffered I/O requests associated with the decnet+ devices.
But without a crash dump to enjoy its hard to say.
____________________
Purely Personal Opinion
Wim Van den Wyngaert
Honored Contributor

Re: Non-paged dynamic memory

Sorry but too late for the crash dump. I'll take one next time.

I took the source of the application and it seems Volker is right. There is a dassgn missing (or my C knowledge is too bad and I misunderstood the coding).

Wim
Wim
Wim Van den Wyngaert
Honored Contributor

Re: Non-paged dynamic memory

Volker and others,

Same problem again on a different node. This time with a crash dump.

This time all non paged dynamic memory is gone (and node went into hang). Show pool/sum shows 52% is going to type unknown. Any suggestions ?

Wim
Wim