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HP OpenVMS System Analysis Tools Manual
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Chapter 6
SDA FLT Extension

The Alignment Fault Utility (FLT) finds alignment faults and records them in a ring buffer, which can be sized when starting alignment fault tracing. The summary screen displays the results sorted by the program counter (PC) that has incurred the most alignment faults. The detailed trace output also shows the process identification (PID) of the process that caused the alignment fault, with the virtual address that triggered the fault.

Output can be directed to a file using the SDA SET OUTPUT command.

FLT can be started and stopped as required without the need for a system reboot.

6.1 FLT Commands

Table 6-1 summarizes the commands for the FLT utility.

Table 6-1 Commands for the Alignment Fault Utility
Commands Description
FLT LOAD Loads the FLT$DEBUG execlet.
FLT UNLOAD Unloads the FLT$DEBUG execlet.
FLT START TRACE Starts alignment fault tracing.
FLT Lists the FLT commands.
FLT STOP TRACE Stops tracing.
FLT SHOW TRACE Displays detailed information about the trace.

The end of this chapter has an example of how you might use these FLT commands.

FLT

When entered with no keywords, lists the FLT commands.

Format

FLT

Parameters

None.

Qualifiers

None.

FLT LOAD

Loads the FLT$DEBUG execlet. Do this before starting alignment fault tracing.

Format

FLT LOAD

Parameters

None.

Qualifiers

None.

FLT SHOW TRACE

Displays detail about the trace.

Format

FLT SHOW TRACE [/SUMMARY [/RATES (d) | /TOTALS]]

Parameters

None.

Qualifiers

/RATES

When used with /SUMMARY, the alignment fault rate per second for each PC during the collection interval is displayed. This is the default.

/SUMMARY

Displays the results sorted by the program counter (PC) that has incurred the most alignment faults.

/TOTALS

When used with /SUMMARY, the total number of alignment faults for each PC during the collection interval is displayed.

FLT START TRACE

Starts alignment fault tracing. By default, all PCs are traced.

Format

START TRACE [/BUFFER=pages] [/BEGIN=pc_range_low]
[/CALLER] [/END=pc_range_high]
[/INDEX=pid] [MODE=(mode,...)]

Parameters

None.

Qualifiers

/BUFFER=pages

The number of pages to size the trace buffer. The default is 128 pages or 1MB.

/BEGIN=pc_range_low

Start of range of PCs to trace.

/CALLER

For each alignment fault, in addition to recording the PC that incurred the fault, FLT also records the PCs of the caller, the callers caller, and so on, for up to 10 call frames.

/END=pc_range_high

End of range of PCs to trace.

/INDEX=pid

Only trace alignment faults for the specified process. You can specify the process index itself, or the process identification or extended process identification, from which the process index is extracted.

/MODE=(mode,...)

Only trace alignment faults that occur in the specified modes. Allowed modes are KERNEL, EXEC, SUPER and USER. If you specify only one mode, you can omit the parentheses.

FLT STOP TRACE

Stops tracing.

Format

FLT STOP TRACE

Parameters

None.

Qualifiers

None.

FLT UNLOAD

Unloads the FLT$DEBUG execlet.

Format

FLT UNLOAD

Parameters

None.

Qualifiers

None.

Example 6-1 Example 

SDA> flt load 
SDA> flt start trace 
 . 
 . 
 . 
SDA> flt show trace /summary 
 
Fault Trace Information: (at 12-OCT-2004 16:09:29.43, trace time 00:00:55.145335) 
--------------------------------------------------------------------------------- 
Exception PC               Count   Exception PC                            Module                      Offset 
-----------------   ------------   --------------------------------------  ---------------------------------- 
FFFFFFFF.86214790            973   RDMSHRP72+0019E790                      RDMSHRP72                 0019E790 
FFFFFFFF.86214791            871   RDMSHRP72+0019E791                      RDMSHRP72                 0019E791 
FFFFFFFF.8620B261            700   RDMSHRP72+00195261                      RDMSHRP72                 00195261 
FFFFFFFF.8620B260            700   RDMSHRP72+00195260                      RDMSHRP72                 00195260 
FFFFFFFF.841C3451            208   LIBRTL+00195451                         LIBRTL                    00195451 
FFFFFFFF.818E43E0            193   NET$TRANSPORT_NSP+303E0                 NET$TRANSPORT_NSP         000303E0 
FFFFFFFF.818E4400            193   NET$TRANSPORT_NSP+30400                 NET$TRANSPORT_NSP         00030400 
FFFFFFFF.818E4430            193   NET$TRANSPORT_NSP+30430                 NET$TRANSPORT_NSP         00030430 
FFFFFFFF.818E4450            193   NET$TRANSPORT_NSP+30450                 NET$TRANSPORT_NSP         00030450 
FFFFFFFF.818E44B1            193   NET$TRANSPORT_NSP+304B1                 NET$TRANSPORT_NSP         000304B1 
FFFFFFFF.818E44D0            193   NET$TRANSPORT_NSP+304D0                 NET$TRANSPORT_NSP         000304D0 
FFFFFFFF.818E6720            186   NET$TRANSPORT_NSP+32720                 NET$TRANSPORT_NSP         00032720 
FFFFFFFF.818E64C0            179   NET$TRANSPORT_NSP+324C0                 NET$TRANSPORT_NSP         000324C0 
FFFFFFFF.818E6520            179   NET$TRANSPORT_NSP+32520                 NET$TRANSPORT_NSP         00032520 
FFFFFFFF.86DE9480            166   RDMSHRP72+00D73480                      RDMSHRP72                 00D73480 
FFFFFFFF.807814A1            162   EXE$SETOPR_C+00841                      MESSAGE_ROUTINES          0001D7A1 
FFFFFFFF.86DE8C90            146   RDMSHRP72+00D72C90                      RDMSHRP72                 00D72C90 
FFFFFFFF.86DE8EC0            146   RDMSHRP72+00D72EC0                      RDMSHRP72                 00D72EC0 
FFFFFFFF.8701C340            146   RDMSHRP72+00FA6340                      RDMSHRP72                 00FA6340 
FFFFFFFF.862026E1            100   RDMSHRP72+0018C6E1                      RDMSHRP72                 0018C6E1 
FFFFFFFF.86202580            100   RDMSHRP72+0018C580                      RDMSHRP72                 0018C580 
FFFFFFFF.862025B0            100   RDMSHRP72+0018C5B0                      RDMSHRP72                 0018C5B0 
FFFFFFFF.8701B900             83   RDMSHRP72+00FA5900                      RDMSHRP72                 00FA5900 
00000000.000EE990             37                                                                     
00000000.000EEA51             37                                                                     
00000000.000EE8D1             37                                                                     
FFFFFFFF.807359C1             28   LOCKING+253C1                           LOCKING                   000253C1 
FFFFFFFF.807359F1             28   LOCKING+253F1                           LOCKING                   000253F1 
FFFFFFFF.80732EE0             27   LCK$FILL_RSB_CACHE_C+008F0              LOCKING                   000228E0 
FFFFFFFF.86DE8690             18   RDMSHRP72+00D72690                      RDMSHRP72                 00D72690 
FFFFFFFF.80B388A0             15   SECURITY+461A0                          SECURITY                  000461A0 
FFFFFFFF.80B213F0             13   NSA$SIZE_NSAB_C+00840                   SECURITY                  0002ECF0 
FFFFFFFF.86DFE9E0             12   RDMSHRP72+00D889E0                      RDMSHRP72                 00D889E0 
[...............] 
 
 
SDA> flt show trace 
 
Unaligned Data Fault Trace Information: 
--------------------------------------- 
Timestamp              CPU  Unaligned VA       Exception PC                            Access      EPID    Trace Buffer 
---------------------- ---  -----------------  --------------------------------------  --------  --------  ----------------- 
12-OCT 16:09:56.439499  02  00000000.014A4F8A  86214791 RDMSHRP72+0019E791             Exec      39C004DC  FFFFFFFF.74921610 
12-OCT 16:09:56.439493  02  00000000.023DFFD4  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.749215E8 
12-OCT 16:09:56.439486  02  00000000.014A4F42  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.749215C0 
12-OCT 16:09:56.439480  02  00000000.014A4F8A  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.74921598 
12-OCT 16:09:56.439254  02  00000000.0154F1DC  807814A1 EXE$SETOPR_C+00841             Exec      39C004DC  FFFFFFFF.74921570 
12-OCT 16:09:56.431606  02  00000000.014A4F5A  86214791 RDMSHRP72+0019E791             Exec      39C004DC  FFFFFFFF.74921548 
12-OCT 16:09:56.431601  02  00000000.022DEE44  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.74921520 
12-OCT 16:09:56.431594  02  00000000.014A4F42  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.749214F8 
12-OCT 16:09:56.431588  02  00000000.014A4F5A  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.749214D0 
12-OCT 16:09:56.430255  02  00000000.0155BDDC  807814A1 EXE$SETOPR_C+00841             Exec      39C004DC  FFFFFFFF.749214A8 
12-OCT 16:09:56.426878  02  00000000.014A4F72  86214791 RDMSHRP72+0019E791             Exec      39C004DC  FFFFFFFF.74921480 
12-OCT 16:09:56.426872  02  00000000.02394ED4  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.74921458 
12-OCT 16:09:56.426865  02  00000000.014A4F42  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.74921430 
12-OCT 16:09:56.426859  02  00000000.014A4F72  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.74921408 
12-OCT 16:09:56.426583  02  00000000.0154A97C  807814A1 EXE$SETOPR_C+00841             Exec      39C004DC  FFFFFFFF.749213E0 
12-OCT 16:09:56.421244  02  00000000.014A4F52  86214791 RDMSHRP72+0019E791             Exec      39C004DC  FFFFFFFF.749213B8 
12-OCT 16:09:56.421238  02  00000000.02296824  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.74921390 
12-OCT 16:09:56.421232  02  00000000.014A4F42  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.74921368 
12-OCT 16:09:56.421226  02  00000000.014A4F52  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.74921340 
12-OCT 16:09:56.420916  02  00000000.0156405C  807814A1 EXE$SETOPR_C+00841             Exec      39C004DC  FFFFFFFF.74921318 
12-OCT 16:09:56.413932  02  00000000.014A4F52  86214791 RDMSHRP72+0019E791             Exec      39C004DC  FFFFFFFF.749212F0 
12-OCT 16:09:56.413926  02  00000000.023C10D4  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.749212C8 
12-OCT 16:09:56.413918  02  00000000.014A4F42  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.749212A0 
12-OCT 16:09:56.413913  02  00000000.014A4F52  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.74921278 
12-OCT 16:09:56.413645  02  00000000.01564E9C  807814A1 EXE$SETOPR_C+00841             Exec      39C004DC  FFFFFFFF.74921250 
12-OCT 16:09:56.403972  02  00000000.014A4F52  86214791 RDMSHRP72+0019E791             Exec      39C004DC  FFFFFFFF.74921228 
12-OCT 16:09:56.403966  02  00000000.023036C4  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.74921200 
12-OCT 16:09:56.403960  02  00000000.014A4F42  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.749211D8 
12-OCT 16:09:56.403954  02  00000000.014A4F52  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.749211B0 
12-OCT 16:09:56.403689  02  00000000.0155E47C  807814A1 EXE$SETOPR_C+00841             Exec      39C004DC  FFFFFFFF.74921188 
12-OCT 16:09:56.395575  02  00000000.014A4F8A  86214791 RDMSHRP72+0019E791             Exec      39C004DC  FFFFFFFF.74921160 
12-OCT 16:09:56.395569  02  00000000.02448D24  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.74921138 
12-OCT 16:09:56.395562  02  00000000.014A4F42  86214790 RDMSHRP72+0019E790             Exec      39C004DC  FFFFFFFF.74921110 
[....................]

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