BIGPIN Feature: Support Up To 12000 Concurrent Processes
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MPE/iX System Architect
Commercial Systems Division
INTRODUCTION
The maximum number of concurrent processes (sometimes referred to as MAXPIN) has been a key constraint limiting MPE/iX in high-growth, high-end customer environments. Removing this constraint is one of the key ingredients in Hewlett-Packard's continuing strategy to evolve MPE/iX -- providing growth for our high-end customers. The new MAXPIN limit in MPE/iX Release 7.0 Express 1 has been raised from 8190 to 12000. MPE/iX Release 7.0 Express 1 contains a new SYSGEN feature, which allows customers to enable support for greater than 8190 concurrent processes (referred to as BIGPIN).
| Feature | Base MPE/iX 7.0 Release | MPE/iX Release 7.0 Express 1 |
|---|---|---|
| Core OS support for > 8190 concurrent processes | Yes (cannot be enabled) | Yes (disabled by default - can be enabled with SYSGEN) |
| Maximum value for MAXPIN.(Actual value for a given system will be determined by the MAXPIN scaling algorithm) | 8190 | 12000 (Requires > 2GB memory, BIGPIN enabled, and is restricted to N-Class systems). |
| Enhanced "Program File Event" Logging | Yes | Yes |
| SYSGEN>misc>system bigpin=on feature | No | Yes |
| HPMAXPIN CI Variable | Yes | Yes |
| Improved MAXPIN scaling algorithm | Yes | Yes |
| All HP products and subsystem have been modified to support > 8190 concurrent processes. | No | Yes |
WHO SHOULD READ THIS ARTICLE?
High-end customers
System Administrators for high-end systems
Third-party software developer (or customers) with privileged applications and/or applications that explicitly use Process Identification Numbers.
This article contains:
A very brief overview of internal changes to MPE/iX (and the relevant potential external impact).
Discussion of the BIGPIN feature
Description of new/enhanced "Program File Event" logging feature, which logs potential issues on a customer system.
Description of the new MAXPIN Scaling algorithm.
Discussion of 5-digit PIN numbers (and changes to :SHOWQ and :SHOWPROC commands).
OVERVIEW OF INTERNAL OS CHANGES
The MPE/iX concurrent process limit has historically been limited by one of Process Management data structures called the Process Control Block (PCB). The PCB data structure predates MPE/iX as the key process management data structure on older MPE/V-based operating systems. The PCB was ported to MPE/iX and has existed as a Compatibility Mode data structure. The PCB is very heavily referenced by various components of the Compatibility Mode Operating System. Over the years, there have been many changes to the PCB data structure that have expanded its capacity. Starting with MPE/iX Release 7.0, the PCB has been rearchitected as Native Mode data structure. The PCB changes have been designed for maximal backward compatibility. As a result, existing CM or NM code which accesses the PCB should function correctly, (without modification) provided there are less than 8190 processes on the system.
BIGPIN Concept
MPE/iX Release 7.0 introduced the concept of "BIGPIN." The term BIGPIN refers to a system's ability to support greater than 8190 concurrent processes. In MPE/iX Release 7.0 the CORE OS is BIGPIN capable; but the BIGPIN feature (which is Configurable) could not be enabled. In MPE/iX Release 7.0 Express 1 customers can enable the BIGPIN feature in sysgen. The "system" command, which is available in the "misc" area of sysgen, has been modified to enable/disable the BIGPIN feature. To enable BIGPIN do the following:
sysgen
[snip ...]
sysgen> misc
[snip ...]
misc> system bigpin=on
misc> show system
SYSTEM command parameter VALUE
----------------- ----------- -----
USER VERSION userversion C.38.07
LOGON PROMPT logonprompt MPE/iX:
CI PROMPT ciprompt :
RELEASE X.70.14
ENFORCE LOGON UDCS enforcelogonudcs OFF
> 8K PROCESSES bigpin ON
EVENT LOGGING
MPE/iX has been enhanced to log, at runtime, certain events where programs execute operations that will not function correctly if the BIGPIN feature is enabled. Customers are encouraged to make sure that this event logging facility is enabled (which it should be by default) when they upgrade to Release 7.0. In particular, high-end customers who are potential candidates for turning on the BIGPIN feature (in a future release of MPE/iX) are encouraged to examine their system log files -- looking specifically for the new BIGPIN related events (described below). If any BIGPIN events are logged on a customer's system, the customer will need to contact the company responsible for the software in question. Hewlett-Packard will be making changes to some additional software products in future release of MPE/iX. There should be no BIGPIN related events logged by the MPE/iX operating system. If there are any events logged by MPE, please contact your HP support representative with all the details. For software supported by third-party software vendors, contact the vendor directly. Hewlett-Packard will be working with our software vendors to ensure they can make any necessary changes to support greater than 8190 concurrent processes.
 |
NOTE: The event logging facility is designed to catch specific runtime events that will cause a problem ON SYSTEMS WITH GREATER THAN 8190 PROCESSES. None of these events represents issues on systems with less than or equal to 8190 processes. Furthermore, these events are expected to be relatively rare. For the most part, the kinds of operations that can potentially cause problems are fairly obscure. It is not "common" for third-party or customer software to reference the PCB (or other OS internal data structures) directly. Such references are limited to lower-level privileged mode applications. This is not expected to be a significant issue for customers as we move forward with a plan to support greater than 8190 processes. The event-logging facility should be viewed as a "safety net," designed to give HP and our customer's "piece of mind" as we make this transition. |
HOW TO MAKE SURE PROGRAM EVENT FILE LOGGING IS ENABLED
The "SYSGEN>log/show slog" command can be used to display the current setting for various system logging events. The "status" corresponding to the "Program File Event" (event number 116) must be "ON." Example 5-1 SYSGEN>log/show slog
:sysgen
[snip ...]
sysgen> log
[snip ...]
log>show slog
system log events event # status
----------------- ------- ------
System Logging 100 ON
System Up 101 ON
[snip...]
Program File Event 116 ON
Native Mode Spooling 120 OFF
[snip...]
DISPLAYING PROGRAM FILE EVENTS
To display all "Program File Event" log records, use the "LOGTOOL>list" command. The list command allows the user to explicitly specify the logging event number in the "type=" parameter. To see only Program File Events, specify "type=116." |
NOTE: On MPE/iX Release 7.0, the LOGTOOL program can be found in PUB.SYS. On some older versions of MPE/iX, LOGTOOL was in DIAG.SYS. |
EVENT TYPE. The "event type" field is used to distinguish different Program File Events. Event types -101, -102, and -103 indicate that a program performed an action that will not work properly with greater than 8190 process (BIGPIN=true). These events are described in detail below.
PROGRAM FILE NAME. This field contains the name of the program file corresponding to the program that has the issue. See "When/How Are Events Logged" below.
LOGTOOL>list log=587 type=116
SYSTEM ERROR LOG REPORT
=======================
Report Date/Time: THU, DEC 7, 2000 - 6:47 PM
=======================================================================
THU, DEC 7, 2000 6:45 PM LOG0587.PUB.SYS #S3 (PIN 74)
PROGRAM FILE EVENT
EVENT TYPE: BIGPIN:Get'My'PCB'Offset DELTA P: $0
STATUS: $0 PROGRAM FILE NAME:
PPINTEST.TESTPINS.SYS
NM OFFSET: $0 USER: MANAGER
GROUP: TESTPINS ACCOUNT: SYS
JSNAME: USER: MANAGER
GROUP: TESTPINS ACCOUNT: SYS
JSNAME:
=======================================================================
THU, DEC 7, 2000 6:45 PM LOG0587.PUB.SYS #S3 (PIN 74)
PROGRAM FILE EVENT
EVENT TYPE: BIGPIN:SST 3 DELTA P: $0
STATUS: $0 PROGRAM FILE NAME:
PPINTEST.TESTPINS.SYS
NM OFFSET: $0 USER: MANAGER
GROUP: TESTPINS ACCOUNT: SYS
JSNAME: USER: MANAGER
GROUP: TESTPINS ACCOUNT: SYS
JSNAME:
=======================================================================
THU, DEC 7, 2000 6:45 PM LOG0587.PUB.SYS #S3 (PIN 74)
PROGRAM FILE EVENT
EVENT TYPE: BIGPIN: LST 3 DELTA P: $0
STATUS: $0 PROGRAM FILE NAME:
PPINTEST.TESTPINS.SYS
NM OFFSET: $0 USER: MANAGER
GROUP: TESTPINS ACCOUNT: SYS
JSNAME: USER: MANAGER
GROUP: TESTPINS ACCOUNT: SYS
JSNAME:
=======================================================================
TYPE DESCRIPTION COUNT
====== ==================== ==========
116 PROGRAM FILE EVENT 3
====== ==================== ==========
Total records checked = 117. Records selected = 3.
***********************************************************************
[Report Completed]
WHEN/HOW ARE EVENTS LOGGED?
At runtime, if a program executes an operation that is not BIGPIN compatible, MPE/iX will set a flag indicating that "event" occurred. When a process terminates, MPE/iX checks to see if any such flags are set; and, if so, it invokes the system logging facility to log the actual events (as Program File Event - type 116 - log records). Any given event will only be logged once for any given process (after that process terminates). It does not matter how many times a given process performs a given operation, the event will only be logged once.SPECIFIC BIGPIN EVENTS
The table below lists all of the "Program File Events" that can potentially be logged. The "text" field refers to the "text" displayed (by LOGTOOL) in the "Event Type" field (see example above). The "Number" field is the actual numeric value associated with that Event Type.| EVENT TYPE | Description | |
|---|---|---|
| Text | Number | |
| cm_tos_reg_fixup | -1 | Not a BIGPIN related event. The CM instruction emulator has taken an action on behalf of the user to fix-up a correctable addressing problem. No action is required if this event is logged. |
| BIGPIN:LST 3 | -101 | Program executed a CM "LST 3" instruction. |
| BIGPIN:SST 3 | -102 | Program executed a CM "SST 3" instruction. |
| BIGPIN:Get'My'PCB'Offset | -103 | Program called Get'My'PCB'Offset |
| BIGPIN:AWAKE | -201 | Program called AWAKE |
| BIGPIN:UNIMPEDE | -202 | Program called UNIMPED |
| BIGPIN:LABEL'IS'SL'SEG | -203 | Program called LABEL'IS'SL'SEG |
| BIGPIN:MARKER'IS'SL'SEG | -204 | Program called MARKER'IS'SL'SEG |
| BIGPIN:FREEZE | -205 | Program called FREEZE |
| BIGPIN:UNFREEZE | -206 | Program called UNFREEZE |
| BIGPIN:LOCKSEG | -207 | Program called LOCKSEG |
| BIGPIN:UNLOCKSEG | -208 | Program called UNLOCKSEG |
| BIGPIN:LOGICALCST' | -209 | Program called LOGICALCST' |
| BIGPIN:SEG'FROM'RTMSL | -210 | Program called SEG'FROM'RTMSL |
| BIGPIN:TIMEREQ | -211 | Program called TIMEREQ |
|
NOTE: These programs should work properly as long as the BIGPIN feature is not turned on. The BIGPIN feature cannot be enabled on Release 7.0, but will be available in a future Release of MPE/iX. |
| Program "owner" | Action |
|---|---|
| Third-party software vendor. | Contact that vendor for more information. |
| In-house written program. | Contact HP Support to get information on how to modify the program so that it will work correctly with BIGPIN enabled. |
| Unsure? | Contact your Hewlett-Packard support representative for help. |
| Hewlett-Packard | Report this to your Hewlett-Packard support representative. Currently there are no pieces of software where this is "expected." |
MAXPIN SCALING CHANGES
MPE/iX is a "one size fits all" operating system. The same version of MPE/iX runs on a broad range of systems - ranging from very low-end systems to very high-end (Enterprise Class) systems. MPE/iX has a feature known as "MAXPIN scaling." The purpose of MAXPIN scaling is to limit the MAXPIN value on low-end machines to a more appropriate number, and to scale the size of various OS data structures accordingly. The MAXPIN scaling algorithm improves resource utilization on low-end system (especially with respect to resident memory usage). The MAXPIN scaling algorithm has been around for several MPE/iX releases (originally introduced when MAXPIN was increased from 1559 to 3119 - Release 2.0 timeframe). When this algorithm was originally introduced, we supported several systems with VERY small minimum memory requirements. Many of these systems are now obsolete. The original algorithm was not updated to reflect changes in the HP e3000 product line. In Release 7.0, we have a new MAXPIN scaling algorithm that is much more appropriate, given today's low-end systems, and takes into account future enhancements to MPE/iX. These improvements will continue to increase the maximum MAXPIN value for future high-end systems. The original MAXPIN-scaling adjusted MAXPIN based on the amount of physical memory on a system. This will continue to be the case for Release 7.0. However, the algorithm uses a different physical memory values and different MAXPIN values. In the future, additional criteria may be added to the algorithm. In MPE/iX Release 7.0 Express 1, support for greater than 8190 processes will require > 2 GB of memory, the BIGPIN feature must be enabled, and the system must be an N-Class system. Below is a table that compares the MAXPIN scaling values for Release 6.5 (and before) and to MPE/iX Release 7.0 Express 1 scaling values.
Physical Memory (m) <= MPE/iX Release 6.5 MPE/iX Release 7.0 m < 32 MB 200 400 [2] 32 MB <= m < 48 MB 400 400 [2] 48 MB <= m < 64 MB 3000 400 [2] m = 64 MB 5460 400 [2] m > 64 MB 8190 400 [2] m <= 64 MB n/a [3] 400 64 MB < m <= 256 MB 8190 [4] 1000 256 MB < m <= 512 MB 8190 [4] 2000 512 MB < m <= 1 GB 8190 [4] 4000 1 GB < m <= 2 GB 8190 [4] 8190 m > 2 GB 8190 [4] 8190/12000 [1]
For MPE/iX Release 7.0 Express 1 the maximum MAXPIN value will be 12000 if the system has > 2GB of memory, is an N-Class system, and BIGPIN has been enabled in SYSGEN. Otherwise, the maximum MAXPIN value is 8190..
All of these cases fall into the "m <= 64 MB" case on 7.0.
The "m <= 64 MB" case was broken down into finer granularity for MPE/iX releases prior to 7.0.
On MPE/iX 6.5 (and earlier), any system with greater than 64 MB of memory was allowed MAXPIN equal to the maximum MAXPIN value for that release. On 6.5, maximum MAXPIN was 8190.
HPMAXPIN VARIABLE
A new system variable, HPMAXPIN, has been defined in Release 7.0. HPMAXPIN will return the maximum number of concurrent processes supported on any given system. HPMAXPIN is a standard, pre-defined integer, read-only CI variable. Example 5-3 HPMAXPIN VARIABLE
:help hpmaxpin
HPMAXPIN The maximum number of concurrent processes supported on this
system.
Type= Read-only, Integer
:showvar hpmaxpin
HPMAXPIN = 1000
FIVE DIGIT PIN NUMBERS
Starting with MPE/iX Release 7.0, developers should ensure that their software is capable of handling PIN numbers greater than 8190. Once we support greater than 8190 processes, we will also be supporting > 9999. This means that PINs will require more than 4 ASCII digits to be represented in decimal. Third-party software developers and customers are encouraged to examine their software to ensure it is capable of handling 5-digit PIN numbers. There are a variety of ways that code can be affected by the change from 4- to 5-digit PINs. An obvious example is code that displays PIN number, but does not reserve enough room for 5-digits. A subtler example is code that uses the PIN to construct a unique temporary file name. If that code appends a 5-digit PIN to a "prefix" that is 4 digits, the size of the file name will overflow the 8 character limit (for MPE filenames). There are two MPE/iX CI commands that assume 4-digit PIN numbers in their command output. The two commands are :SHOWQ and :SHOWPROC. The MPE/iX development team worked with a set of key third-party software developers to determine the "best" way to change :SHOWQ and :SHOWPROC to accommodate 5-digit PIN numbers. In deciding the "best" approach, we had to evaluate two (somewhat) mutually exclusive objectives:
Backward compatibility. Minimal (or ideally zero) impact to existing programs and scripts that may parse output from :SHOWQ and/or :SHOWPROC.
Human readability. Making the output as easy to read as possible, on a terminal, by an end-user.
:SHOWQ
The :SHOWQ command is a much older MPE command - existing long before MPE/iX. The output of :SHOWQ is also much more "column oriented" (compared to :SHOWPROC). In general, users are discouraged from making assumptions regarding specific column numbers in command output. Various CI functions have been added in MPE/iX to assist users in parsing output without relying on column (e.g. the "word" function). However, given the fact that :SHOWQ has been around for a very long time, its columnar output, and given older scripts (etc.) tend to make more assumptions about column, we opted not to change the columns for :SHOWQ output. As a result, 5-digit PIN numbers will "run together" with the field that follows the PIN in :SHOWQ output. Fortunately, the field following PIN in :SHOWQ is a Job/Session number. Job/Session numbers are displayed as #Jxxxxx or #Sxxxxx. As a result, the output from :SHOWQ is still fairly "readable" even if a 5-digit PIN runs together with a Job/Session number. Example 5-4 :SHOWQ OUTPUT
DORMANT RUNNING
Q PIN JOBNUM Q PIN JOBNUM
A 1 C M92 #S80
B 2 D U103 #J362
B 3 D U10951#J60
A 4
[output snipped for brevity]
C M59 #S81C M60 #S49
D U10951#J60
------QUANTUM-------
QUEUE BASE LIMIT MIN MAX ACTUAL BOOST TIMESLICE
----- ---- ----- --- --- ------ ----- ---------
CQ 152 200 1 2000 4 DECAY 200
DQ 202 238 2000 2000 2000 DECAY 200
EQ 240 253 2000 2000 2000 DECAY 200
Example 5-5 COLUMN NUMBERS FOR :SHOWQ
---------------------------- Column Numbers ------------------------- 1 2 3 4 5 6 7 12345678901234567890123456789012345678901234567890123456789012345689 DORMANT RUNNING Q PIN JOBNUM Q PIN JOBNUM L Lddddd#Lddddd L Lddddd#Lddddd Key: L = Letter d = Digit (decimal) # = # character
:SHOWPROC
The :SHOWPROC command is a fairly new MPE/iX command. In addition, the output from :SHOWPROC is not columnar by nature. In particular, for the :SHOWPROC ;TREE command, it would be very difficult to parse the output using column numbers. Given all these reasons, we decided to change :SHOWPROC output to display PIN numbers in a field wide enough for 5-digits followed by a space (separating the PIN number from the next field on the output line). On Release 7.0, PIN numbers are left justified within the 5-digit field (they are left justified today in a 4-digit field). The :SHOWPROC command can be used in (essentially) three different ways:show invoking process only (default);
show all process in a given job (using the ;JOB= keyword)
show all processes in a given tree (using the ;TREE option).
:SHOWPROC (default) ---------------------------- Column Numbers ------------------------- 1 2 3 4 5 6 7 123456789012345678901234567890123456789012345678901234567890123456789 :showproc QPRI CPUTIME STATE JOBNUM PIN (PROGRAM) STEP C152 0:02.377 READY S9 xxxxx :SHOWPROC --------------------------------------------------------------------- SHOWPROC ;JOB= ---------------------------- Column Numbers ------------------------- 1 2 3 4 5 6 7 123456789012345678901234567890123456789012345678901234567890123456789 :showproc ;job=#j10 QPRI CPUTIME STATE JOBNUM PIN (PROGRAM) STEP D202 0:00.232 WAIT J10 xxxxx :RUN SPFLSTNR.LASER D202 00:13:46 WAIT J10 xxxxx (SPFLSTNR.LASER.LARC) --------------------------------------------------------------------- SHOWPROC ;TREE ---------------------------- Column Numbers ------------------------- 1 2 3 4 5 6 7 123456789012345678901234567890123456789012345678901234567890123456789 :showproc 46;system;tree QPRI CPUTIME STATE JOBNUM PIN (PROGRAM) STEP B100* 0:28.653 WAIT 46 (JOB.PUB.SYS) B152 0:00.224 WAIT J3 xxxxx (JSMAIN.PUB.SYS) D202 0:00.252 WAIT J3 xxxxx :RUN control.trnspool D202 00:11:11 WAIT J3 xxxxx (CONTROL.TRNSPOOL.NSD) D205 00:36:16 WAIT J3 xxxxx (TSENDMXL.TRNSPOOL.NSD) D202 0:27.548 WAIT J3 xxxxx (THREADM.TRNSPOOL.NSD) [snip]
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NOTE: Column numbers are shown above for informational purposes only. Users are encouraged NOT to use column numbers to parse command output. Column numbers are subject to change in future releases of MPE/iX. |
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