HP OpenVMS Systems Documentation

OpenVMS VAX System Dump Analyzer Utility Manual

This SDA session shows the output of the SHOW LOCK command for several locks. The SHOW RESOURCE command, executed for the last displayed lock, verifies that the lock is in the resource's granted queue, among many other locks given concurrent read (CR) access to the resource. (See Table SDA-21 for a full explanation of the contents of the display of the SHOW RESOURCE command.)

SDA SHOW LOCK/CACHE
Lock database
-------------

Lock id:  6D000032   PID:     00010028   Flags:   VALBLK  SYNCSTS SYSTEM
Par. id:  01000002   SUBLCKs:        0            NOQUOTA
LKB:   80F67C00   BLKAST:  00000000
PRIORTY:      0000

Granted at      PW   00000000-FFFFFFFF

Resource:      00257324 42313146    F11B$s%.  Status:  NOQUOTA CACHED
 Length   10   00000000 00000000    ........
 Kernel mode   00000000 00000000    ........
 System        00000000 00000000    ........

Local copy

Lock id:  7B00003B   PID:     0001000B   Flags:   VALBLK  SYNCSTS SYSTEM
Par. id:  01000002   SUBLCKs:        0            NOQUOTA
LKB:   80F51F80   BLKAST:  00000000
PRIORTY:      0000

Granted at      PW   00000000-FFFFFFFF

Resource:      08E97324 42313146    F11B$sé.  Status:  NOQUOTA CACHED
 Length   10   00000000 00000000    ........
 Kernel mode   00000000 00000000    ........
 System        00000000 00000000    ........

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Local copy

This example of the SHOW LOCK/CACHE command displays the contents of cached lock blocks (LKBs).

SHOW LOGS

Displays information about transaction logs currently open for the node.

Format

SHOW LOGS [/qualifier[,...]]

Qualifier

/DISPLAY=(item [,...])
Specifies the type of information to be displayed. The argument to /DISPLAY can be either a single item or a list. The following items can be specified.

Item Description

ALL All transaction log control structure information. This is the default behavior.

OPENS Transaction log open requests.

READS Transaction log read requests.

WRITES Transaction log write requests.

Example


SDA> SHOW LOGS/DISPLAY=(OPENS, WRITES)

The SHOW LOGS command displays the log open request and log write request information for all open transaction logs for the node.

SHOW PAGE_TABLE

Displays a range of system page table entries, the entire system page table, or the entire global page table.

Format

SHOW PAGE_TABLE [/qualifier[,...]] [range]

Parameter

range
Range of virtual addresses for which SDA is to display page table entries. You can express a range using the following format:

m:n Range of virtual addresses from m to n

m;n Range of virtual addresses starting at m and continuing for n bytes

Qualifiers

/GLOBAL
Lists the global page table.
/SYSTEM
Lists the system page table.
/ALL
Lists both the global and system page tables. This is the default behavior of SHOW PAGE_TABLE.

Description

For each virtual address displayed by the SHOW PAGE_TABLE command, the first six columns of the listing provide the associated page table entry and describe its location, characteristics, and contents (see Table SDA-16). SDA obtains this information from the system page table.
If the virtual page has been mapped to a physical page, the last nine columns of the listing include information from the page frame number (PFN) database (see Table SDA-17). Otherwise, the section is left blank.
SDA indicates pages are inaccessible by displaying the following message:
-------- n NULL PAGES
Here, n indicates the number of inaccessible pages.

Table SDA-16 Virtual Page Information in the SHOW PAGE_TABLE Display
Value Meaning

ADDRESS System virtual address that marks the base of the virtual page.

SVAPTE System virtual address of the page table entry that maps the virtual page.

PTE Contents of the page table entry, a longword that describes a system virtual page.

Type Type of virtual page. There are the following eight types:

VALID
Valid page (in main memory).
TRANS
Transitional page (between main memory and page lists).
DZERO
Demand-allocated, zero-filled page.
PGFIL
Page within a paging file.
STX
Section table's index page.
GPTX
Index page for a global page table.
IOPAG
Page in I/O address space.
NXMEM
Page not represented in physical memory. The page frame number (PFN) of this page is not mapped by any of the system's memory controllers. This indicates an error condition.

PROT Protection code, derived from bits in the PTE, that designates the type of access (read or write, or both) granted to processor access modes (kernel, executive, supervisor, or user).

Bits Letters that represent the setting of a bit or a combination of bits in the PTE. These bits indicate attributes of a page. The following codes are listed:

M
Page has been modified.
L
Page is locked into a working set.
K
Owner can access the page in kernel mode.
E
Owner can access the page in executive mode.
S
Owner can access the page in supervisor mode.
U
Owner can access the page in user mode.

Table SDA-17 Physical Page Information in the SHOW PAGE_TABLE Display
Category Meaning

PAGTYP Type of physical page. One of the following six types:

PROCESS
Page is part of process space.
SYSTEM
Page is part of system space.
GLOBAL
Page is part of a global section.
PPGTBL
Page is part of a process's page table.
GPGTBL
Page is part of a global page table.
GBLWRT
Page is part of a global, writable section.

LOC Location of the page within the system. One of the following eight locations:

ACTIVE
Page is in a working set.
MDFYLST
Page is in the modified page list.
FREELST
Page is in the free page list.
BADLST
Page is in the bad page list.
RELPEND
Release of the page is pending.
RDERROR
Page has had an error during an attempted read operation.
PAGEOUT
Page is being written into a paging file.
PAGEIN
Page is being brought into memory from a paging file.

STATE Byte that describes the state of the physical page.

TYPE Byte that describes the type of virtual page. The types in this column are the hexadecimal codes that stand for the page types that appear in column PAGTYP of this display, described previously.

REFCOUNT Count of the processes that are referencing this PFN. If the value of REFCOUNT is nonzero, the page is used in at least one working set. If the value is zero, the page is not used in any working set.

BAK Address of the backing store; location on a disk device to which pages can be written.

SVAPTE Virtual address associated with this page frame. The two SVAPTEs indicate a valid link between physical and virtual address space.

FLINK Forward link within PFN database that points to the next virtual page. This longword also acts as the count of the number of processes that are sharing this global section.

BLINK Backward link within PFN database. Also acts as an index into the working set list.

Example

SDA>SHOW PAGE_TABLE
System page table
-----------------

ADDRESS  SVAPTE   PTE      TYPE  PROT  BITS PAGTYP LOC  STATE TYPE REFCNT BAK     SVAPTE    FLINK      BLINK
   .
   .
   .
8014B000 8AD22E00 F8020725 VALID UR       K
8014B200 8AD22E04 F8020726 VALID UR       K
8014B400 8AD22E08 F8020727 VALID UR       K
8014B600 8AD22E0C F8020728 VALID UR       K
8014B800 8AD22E10 F8020729 VALID UR       K
8014BA00 8AD22E14 EC02072A VALID UREW  M  K
8014BC00 8AD22E18 F402072B VALID URKW  M  K
   .
   .
   .
8014BE00 8AD22FEC F801F10E VALID UR       K SYSTEM ACTIVE  07  01   1 0040FFF8   8AD22FEC  00000000  00000258
8014C000 8AD22FF0 F801F10F VALID UR       K SYSTEM ACTIVE  07  01   1 0040FFF8   8AD22FF0  00000000  00000257
8014C200 8AD22FF4 F801F173 VALID UR       K SYSTEM ACTIVE  07  01   1 0040FFF8   8AD22FF4  00000000  000004B1
8014C400 8AD22FF8 F801F172 VALID UR       K SYSTEM ACTIVE  07  01   1 0040FFF8   8AD22FF8  00000000  00000301
8014C600 8AD22FFC F801F17F VALID UR       K SYSTEM ACTIVE  07  01   1 0040FFF8   8AD22FFC  00000000  000000F5
8014C800 8AD23000 F801F17E VALID UR       K SYSTEM ACTIVE  07  01   1 0040FFF8   8AD23000  00000000  00000174
8014CA00 8AD23004 7801EBC6 TRANS UR       K SYSTEM FREELST 00  01   0 0040FFF8   8AD23004  0000D38B  0001EBC7
   .
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   .

SHOW PFN_DATA

Displays information that is contained in the page lists and PFN database.

Format

SHOW PFN_DATA [pfn] [/qualifier]

Parameter

pfn
Page frame number (PFN) of the physical page for which information is to be displayed.

Qualifiers

/ALL
Displays the free page list, modified page list, and bad page list. This is the default behavior of the SHOW PFN_DATA command. SDA precedes each list with a count of the pages it contains and its low and high limits.
/BAD
Displays the bad page list. SDA precedes the list with a count of the pages it contains, its low limit, and its high limit.
/FREE
Displays the free page list. SDA precedes the list with a count of the pages it contains, its low limit, and its high limit.
/MODIFIED
Displays the modified page list. SDA precedes the list with a count of the pages it contains, its low limit, and its high limit.
/SYSTEM
Displays the entire PFN database in order by page frame number, starting at PFN 0000.

Description

For each page frame number it displays, the SHOW PFN_DATA command lists information used in translating physical page addresses to virtual page addresses. Table SDA-18 lists the contents of the display.

Table SDA-18 Page Frame Number Information in the SHOW PFN_DATA Display
Item Contents

PFN Page frame number

PTE ADDRESS System virtual address of the page table entry that describes the virtual page mapped into this physical page

BAK Place to find context, as information about this page when all links to this PTE are broken: either an index into a process section table or the number of a virtual block in the paging file

REFCNT Number of references being made to this page

FLINK Address of the next page in the list in which this virtual page currently resides

BLINK Address of the previous page in the list in which this virtual page currently resides

TYPE Type of virtual page; one of the following:

00
Process page
01
System page
02
Global, read-only page
03
Global, read/write page
04
Process page-table page
05
Global page-table page

STATE State of the virtual page, the low nibble of which can be one of the following:

0
Page is on the free page list.
1
Page is on the modified page list.
2
Page is on the bad page list.
3
Release of the page to the free or modified page list is pending.
4
Error occurred as the page was being read from the disk.
5
Modified page writer is currently writing the page to the disk.
6
Page fault handler is currently reading the page from the disk.
7
Page is active and valid.

Example

SDA>SHOW PFN_DATA
Free page list
--------------
Count:             225
Low limit:          57
High limit: 1073741824
PFN   PTE ADDRESS   BAK     REFCNT FLINK BLINK    TYPE        STATE
----  ----------- --------  ------ ----- -----  ----------  ----------
1329    8047AF3C  03002A83      0   1963 0000   00 PROCESS  00 FREELST
1963    8047AB10  03002A43      0   017C 1329   00 PROCESS  00 FREELST
017C    8047B3F8  03002A84      0   14B4 1963   00 PROCESS  00 FREELST
14B4    8047B464  03002A85      0   1529 017C   00 PROCESS  00 FREELST
1529    8047AA34  03002A87      0   1485 14B4   00 PROCESS  00 FREELST
1485    8047AC80  030010B3      0   1707 1529   00 PROCESS  00 FREELST
   .
   .
   .

In this example, the SHOW PFN_DATA command displays the information for the free page list, the modified page list, and the bad page list, and then all of the PFN database, including the first three lists.

SHOW POOL

Displays information about the disposition of paged and nonpaged memory, nonpaged dynamic storage pool, and paged dynamic storage pool.

Format

SHOW POOL [range][/ALL|/FREE|/HEADER|/NONPAGED| /PAGED|/RING_BUFFER|/STATISTICS| /SUMMARY|/TYPE=block-type]

Parameters

range
Range of virtual addresses in pool that SDA is to examine. You can express a range using the following format:

m:n Range of virtual addresses in pool from m to n

m;n Range of virtual addresses in pool starting at m and continuing for n bytes

Qualifiers

/ALL
Displays the entire contents of allocated pool, including the pool lists, nonpaged dynamic storage pool, and paged dynamic storage pool. This is the default behavior of the SHOW POOL command.
/FREE
Displays the entire contents, both allocated and free, of the specified region or regions of pool. You cannot use the /FREE qualifier when you use a range to indicate a region of pool to be displayed.
/HEADER
Displays only the first 16 longwords of each data block found within the specified region or regions of pool.
/NONPAGED
Displays the contents of the nonpaged dynamic storage pool currently in use.
/PAGED
Displays the contents of the paged dynamic storage pool currently in use.
/RING_BUFFER
Displays the contents of the nonpaged pool history ring buffer if pool-checking has been enabled. Entries are displayed in reverse chronological order, that is, the most recent to the least recent. You cannot use this qualifier with any other SHOW POOL qualifier. This qualifier is most useful when analyzing crash dumps; output might not be consistent when used on a running system.
/STATISTICS
Displays usage statistics about each pool list if pool-checking has been enabled. For each list, the following are displayed:

Queue header address
Packet size
Attempts, failures, and deallocations
SDA does not synchronize its access to these last three counters with other CPUs in a symmetric multiprocessing (SMP) system. Therefore, the numbers might not add up to what you would expect in a multiprocessor configuration. However, the statistics do provide a good indicator of overall pool activity.

/SUMMARY
Displays only an allocation summary for each specified region of pool.
/TYPE=block-type
Displays the blocks within the specified region or regions of pool that are of the indicated block-type. If SDA finds no blocks of that type in the pool region, it displays a blank screen, followed by an allocation summary of the region.

Description

The SHOW POOL command displays information about the contents of any specified region of pool in an 8-column format. Following are explanations and examples of the contents of the full display.
Column 1 contains the type of control block that starts at the virtual address in pool indicated in column 2. If SDA cannot interpret the block type, it displays a block type of "UNKNOWN." Column 3 lists the number of bytes (in decimal) of memory allocated to the block. The block size is fixed for SRPs, IRPs, and LRPs, and is variable in the paged and nonpaged pools. For example:
Col. 1 Col. 2 Col. 3 ------ -------- ------ CIMSG 80BADE00 208
The remaining columns contain a dump of the contents of the block, in 4-longword intervals, until the block is complete. Columns 4 through 7 display, from right to left, the contents in hexadecimal; column 8 displays, from left to right, the contents in ASCII. If the ASCII value of a byte is not a printing character, SDA displays a period (.) instead. For example:
Col. 4 Col. 5 Col. 6 Col. 7 Col. 8 -------- -------- -------- -------- ---------------- 001000DA 003C0090 0000A900 00036FF0 .o........<.Ú... D9B3001C 00000000 A0B5001D 35E60017 ...5............ 41414141 00000600 65EA0004 00000600 .......e....AAAA 41414141 41414141 41414141 41414141 AAAAAAAAAAAAAAAA
For each region of pool it examines, the SHOW POOL command displays an allocation summary. This 4-column table lists, in column 2, the types of control blocks identified in the region and records the number of each in column 1. The last two columns represent the amount of the pool region occupied by each type of control block: column 3 records the total number of bytes, and column 4 records the percentage. The summary concludes with an indication of the number of bytes used within the particular pool region, as well as the number of bytes remaining. It provides an estimate of the percentage of the region that has been allocated. For example:
Col.1 Col. 2 Col.3 Col. 4 ----- ------- ----- ------ 3 UNKNOWN = 176 (29% 2 CIDG = 288 (48% 1 CIMSG = 144 (24%) Total space used = 608 out of 608 total bytes, 0 bytes left Total space utilization = 100%

Examples

SDA> SHOW POOL G0BADE00;260
Non-paged dynamic storage pool
------------------------------
                    Dump of blocks allocated from non-paged pool


CIMSG   80BADE00   144
                     001000DA 003C0090 0000A900 00036FF0 .o........<.....
                     D9B3001C 00000000 A0B5001D 35E60017 ...5............
                     41414141 00000600 65EA0004 00000600 .......e....AAAA
                     41414141 41414141 41414141 41414141 AAAAAAAAAAAAAAAA
                     41414141 41414141 41414141 41414141 AAAAAAAAAAAAAAAA
   .
   .
   .
UNKNOWN 80BADE90   112
                     41414141 41414141 41414141 41414141 AAAAAAAAAAAAAAAA
                     41414141 41414141 41414141 41414141 AAAAAAAAAAAAAAAA
                     41414141 41414141 41414141 41414141 AAAAAAAAAAAAAAAA
                     41414141 41414141 41414141 41414141 AAAAAAAAAAAAAAAA
   .
   .
   .
CIDG    80BADED0   144
                     807708BB 003B0090 0004D7E0 000008F0 ..........;...w.
                     61616161 61616161 61616161 016CE87C ..l.aaaaaaaaaaaa
                     61616161 61616161 61616161 61616161 aaaaaaaaaaaaaaaa
                     61616161 61616161 61616161 61616161 aaaaaaaaaaaaaaaa
   .
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UNKNOWN 80BADF60    64
                     61616161 61616161 61616161 61616161 aaaaaaaaaaaaaaaa
                     61616161 61616161 61616161 61616161 aaaaaaaaaaaaaaaa
                     61616161 61616161 61616161 61616161 aaaaaaaaaaaaaaaa
                     61616161 61616161 61616161 61616161 aaaaaaaaaaaaaaaa
   .
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CIDG    80BADFA0   144
                     807708BB 003B0090 0003FFC0 0004B1B0 ..........;...w.
                     61616161 61616161 61616161 016CE94C L.l.aaaaaaaaaaaa
                     61616161 61616161 61616161 61616161 aaaaaaaaaaaaaaaa
                     61616161 61616161 61616161 61616161 aaaaaaaaaaaaaaaa
   .
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   .
UNKNOWN 80BAE030    48
                     61616161 61616161 61616161 61616161 aaaaaaaaaaaaaaaa
                     61616161 61616161 61616161 61616161 aaaaaaaaaaaaaaaa
                     61616161 61616161 61616161 61616161 aaaaaaaaaaaaaaaa


Summary of non-paged pool contents

    3  UNKNOWN   =      176  (29%)
    2  CIDG      =      288  (48%)
    1  CIMSG     =      144  (24%)

Total space used = 608 out of 608 total bytes, 0 bytes left

Total space utilization = 100%

This example, which uses a range of values, examines 608 (260₁₆) bytes of nonpaged pool, starting at address 80BADE00₁₆. SDA attempts to identify allocated blocks as it proceeds through the specified region of pool, and displays an allocation summary when it completes the listing.

SDA> SHOW POOL/FREE
Non-paged dynamic storage pool
------------------------------

   Dump of blocks allocated from non-paged pool

UNKNOWN 80E7C400 67136
                         0000E53B 80E9EC00 00010000 80F16625 %fñ......ìé.;å..
                         0000E53B 80E9EC00 00010001 80F16625 %fñ......ìé.;å..
                         0000E53B 80E9EC00 00010000 80F166A3 £fñ......ìé.;å..
                         0000E53B 80E9EC00 00010001 80F166A3 £fñ......ìé.;å..
                         0000E53B 80E9EC00 00010000 80F16066 f........ìé.;å..
                         0000E53B 80E9EC00 00010001 80F16066 f........ìé.;å..
                         0000E53B 80E9EC00 00010000 80F16F32 2oñ......ìé.;å..
                         0000E53B 80E9EC00 00010001 80F16F32 2oñ......ìé.;å..
                         0000E53D 80EA1B08 00010000 80F16F48 Hoñ.......ê.=å..
                         0000E53D 80E9EC00 00010001 80F16F48 Hoñ......ìé.=å..
                         0000E53D 80E9EC00 00010000 80F170D8 Øpñ......ìé.=å..
    .
    .
    .

The SHOW POOL/FREE command in this example produces a display similar in format and extent to that presented in Example 1. However, it displays the unallocated portions of pool in addition to those that are used.

SDA>  SHOW POOL/PAGED/HEADER
Paged dynamic storage pool
--------------------------
                    Dump of blocks allocated from paged pool


RSHT    8024FE00   528
                     802DC710 00380210 00000000 FFFFFF80 ..........8...-.
LNM     80250010    96
                     8015B847 00400060 802D75A0 00000000 .....u-.`.@.G...
LNM     80250070    48
                     8015B847 01400030 802500A0 802D7400 .t-...%.0.@.G...
LNM     802500A0    96
                     8015B847 02400060 802DC170 80250070 p.%.p.-.`.@.G...
LNM     80250100    48
                     8015B847 00400030 802DC510 802E1B60 `.....-.0.@.G...
   .
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