sys_attrs_generic(5)						File Formats Manual					      sys_attrs_generic(5)

NAME

       sys_attrs_generic - system attributes for the generic kernel subsystem

DESCRIPTION

       This reference page describes the attributes for the Generic (generic) kernel subsystem.

       Some  of  these	attributes  have corresponding parameters in the system configuration file. If so, the corresponding parameter name in the
       system configuration file is specified in parentheses following the attribute name.  In these cases, never edit	the  system  configuration
       file to directly change the value of the system parameter; change the attribute by using the dxkerneltuner application, the /sbin/sysconfig
       -r command, or the sysconfigdb command. See dxkerneltuner(8), sysconfig(8), and sysconfigdb(8) for more information about your options  for
       configuring kernel subsystems.

	      A value that is set and used internally to support a rolling upgrade operation in a TruCluster environment. Do not modify manually.

	      A value that is set and used internally to support a rolling upgrade operation in a TruCluster environment. Do not modify manually.

	      The kernel buffer size in bytes.

	      Default  value: If the binlog_buffer_size is not explicitly specified, the value for kernel buffer size is assigned at boot time and
	      is based on the amount of physical memory installed on the system. The value assigned automatically ranges from 32  kilobytes  to  1
	      megabyte.

	      Minimum value: 8192 (bytes, or 8 KB)

	      Maximum value: 1,048,576 (bytes, or 1 MB)

	      The arguments that are passed from osf_boot to the kernel. This attribute value is query only.

	      The name of the kernel that was loaded by osf_boot. This attribute value is query only.

	      A  value	that indicates whether the system is (1) or is not (0) an actively running member system in a TruCluster environment. This
	      query-only value is always set to 0 for a standalone system.

	      A value that indicates whether cluster kernel components are (1) or are not (0) configured in the kernel. This query-only  value	is
	      always set to 0 for a standalone system.

	      A value that enables (1) or disables (0) a compressed dump file. The type of zero compression implemented for compression saves sub-
	      stantial disk space but still allows the dump to be read by dbx and other operating system tools.

	      Default value: 1 (enabled)

	      You might want to change the default value if you consistently use tools, such as those from a third party, that do not support com-
	      pressed dump files.  See the System Administration and the Kernel Debuggingmanuals for more information about generating and working
	      with dump files.

	      A value for the bit mask that determines which CPUs are started in a multi-CPU system.  The lowest order bit (bit 0)  in	this  mask
	      corresponds to CPU0. The next highest order bit corresponds to CPU1, and so on, up to bit 63. The bits in these positions can be set
	      to 0 (disabled) or 1 (enabled) for the corresponding CPU slots. The decimal or hexidecimal value specified for cpu_enable_mask  cor-
	      responds to the binary value that has 0 and 1 in the correct ordinal positions for the CPUs you want to enable or disable.

	      Default  value:  The  hex  value corresponding to the slots of CPUs that are actually enabled. On single-CPU systems with the CPU in
	      slot 0, the default value is 0x1.

	      Minimum value: 0

	      Maximum value: 0xffffffffffffffff (or -1)

	      Specifying -1 for this attribute means that all CPUs present in the system are allowed to be started by the master CPU. Specifying 0
	      for this attribute enables uniprocessor operation in a multi-CPU system. Other values enable and disable specific CPUs, depending on
	      what the system supports.

	      The following table illustrates the relationships between bit settings and cpu_enable_mask values for enabling a single CPU.  It	is
	      generally easier to determine and enter hexidecimal values, so only a few significant decimal equivalents are shown:

			 Bit		 Dec.	 Hex		      Single  63...  8	7  6  5 4 3 2 1 0   Value  Value	       CPU Enabled
	      ______________________________________________________________________ 0 ... 0 0 0 0 0 0 0 0 0   0      0 		   Special
	      meaning  * 0 ... 0 0 0 0 0 0 0 0 1   1	  0x1		      CPU0 0 ... 0 0 0 0 0 0 0 1 0	    0x2 		CPU1 0 ...
	      0 0 0 0 0 0 1 0 0 	 0x4		     CPU2 0 ... 0 0 0 0 0 1 0 0 0	   0x8		       CPU3 0 ... 0 0 0 0 1 0 0  0
	      0 	  0x10		      CPU4 0 ... 0 0 0 1 0 0 0 0 0	    0x20		CPU5 0 ... 0 0 1 0 0 0 0 0 0	      0x40
	      CPU6 0 ... 0 1 0 0 0 0 0 0 0	    0x80		CPU7 0 ... 1 0 0 0 0 0 0 0 0	      0x100		  CPU8
		 .
		 .
		 .  1 ... 0 0 0 0 0 0 0 0 0	     0x8000000000000000  CPU63

	      * The minimum value (0) indicates that only the master (boot) CPU be enabled. This value is useful if you want to test  applications
	      in a uniprocessor environment and your test system normally runs in multiprocessor mode.

									      Note

	      Some  systems  require  that the master CPU be CPU0. For these systems, 0, 1, and 0x1 are equivalent entries and are the only values
	      you should specify for uniprocessor operation. On these systems, 0x1 is always the value set for cpu_enable_mask because the  kernel
	      will  overwrite  values  specified  for cpu_enable_mask that are incompatible with having CPU0 as the master CPU. For other systems,
	      users can choose the slot position of the master CPU. Therefore, the result of entering 0 for this attribute can vary. For  example,
	      the actual setting would be 0x2 if CPU1 were the master CPU and 0x10 if CPU4 were the master CPU.

	      The  following  table illustrates the relationships between bit settings and cpu_enable_mask values for enabling sample combinations
	      of CPUs:

			 Bit	       Dec.   Hex		  Multiple 63... 8 7 6 5 4 3  2  1  0	Value	Value		     CPUs  Enabled
	      _________________________________________________________________________  0 ... 0 0 0 0 0 0 0 1 1	 0x3		     CPU0,
	      CPU1 0 ... 0 0 0 0 0 0 1 0 1	   0x5		       CPU0, CPU2 0 ... 0 0 0 0 0 0 1 1 0	  0x6		      CPU1, CPU2 0
	      ... 0 0 0 0 0 0 1 1 1	    0x7 		CPU0, CPU1, CPU2
		 .  0 ... 0 0 0 0 0 1 1 1 1	    0xf 		CPU0 to CPU3
		 .  0 ... 0 0 0 0 1 1 1 1 1	    0x1f		CPU0 to CPU4
		 .  0 ... 0 0 0 1 1 1 1 1 1	    0x3f		CPU0 to CPU5
		 .  0 ... 0 0 1 1 1 1 1 1 1	    0x7f		CPU0 to CPU6
		 .  0 ... 0 1 1 1 1 1 1 1 1	    0xff		CPU0 to CPU7
		 .  0 ... 1 1 1 1 1 1 1 1 1	    0x1ff		CPU0 to CPU8
		 .
		 .
		 .  1 ... 1 1 1 1 1 1 1 1 1  -1     0xffffffffffffffff	All available CPUs *

	      *  The  maximum  value  specifies  1  in	all  bit  positions,  thereby  enabling  all  available  CPUs.	This  value corresponds to
	      18446744073709551615 or -1 in decimal notation and 0xffffffffffffffff in hexidecimal notation.

	      You can enable and disable specific combinations of CPUs by entering values that set and clear appropriate bit positions in the  bit
	      mask.  If  you suspect that one of the CPUs on a multiprocessor system may be the cause of a system problem, you can try running the
	      system with different combinations of available CPUs disabled to help confirm your suspicion. Remember that if your system is one of
	      those  that  require  CPU0 to be the master CPU, the kernel does not apply values that map to 0 in bit position 0. In this case, you
	      have to switch another CPU into slot 0 before you can do a test run that disables the CPU originally in slot 0.

	      Certain lockmode attribute values override incompatible cpu_enable_mask settings.  If the value of the lockmode attribute is 0 or 1,
	      all bits in the cpu_enable_mask bit mask that do not correspond to the master CPU are set to 0.

	      For internal use only. Do not change this attribute value manually.

	      Enables  or  disables  the  inclusion  of  kernel  text  pages. This attribute only applies when partial dumps are enabled (see par-
	      tial_dump). Dumped kernels will be larger.

	      Default value: 0 (disabled)

	      Minimum value: 0 (disabled)

	      Maximum value: 1 (enabled)

	      This value can be changed at run time.

	      A threshold size that determines whether single-partition or multiple-partition dumps are created. If a dump will fit on the primary
	      swap  partition  and  leave space that is  equal to this threshold value, the dump is created as a single-volume dump on the primary
	      swap partition, even if secondary swap partitions are available. (See the System Administration and the Kernel Debugging manuals for
	      details.)

	      Default value: 4096

	      Minimum value: 0

	      Maximum value: 4096

	      This value can be changed at run time.

	      A value that enables (1) or disables (0) dumping to memory.

	      Default value: 0 (disabled)

	      This value can be changed at run time; however, do so only under direction of your support representative.

	      A value that enables (1) or disables (0) the inclusion of user page table entries in a crash dump. Normally, user page table entries
	      contribute no information about the cause of a system crash.

	      Default value: 0 (disabled)

	      This value can be changed at run time. However, you would normally change it only when directed to do so by a support representative
	      who is gathering information about a particular problem.

	      A value that enables (1) or disables (0) asynchronous printing of messages to the console. Asynchronous printing to the console pre-
	      vents large numbers of messages from being written to the console at the same time.

	      Default value: 1 (enabled)

	      This value can be changed at run time. Device driver developers need to set enable_async_printf to 0 when debugging driver  problems
	      because they need to see the results of kernel printf() calls at the time of execution.

	      For internal use only. Do not set this attribute manually. See expected_dump_compression.

	      The level of compression that a dump is typically expected to achieve.

	      Default value: 500

	      Minimum value: 0

	      Maximum value: 1000

	      This  value  can	be changed at run time. See the System Administration manual for instructions on how to calculate the typical dump
	      compression level for your system.

	      For internal use only. Do not set this attribute manually. See dump_user_pte_pages.

	      A value that allows programmers to override file permissions when UNIX domain sockets are created by a bind() call.

	      When insecure_bind is set to a value other than 0, UNIX domain sockets are always created with mode 0777	(the  umask  is  ignored).
	      This prevents bind: permission denied errors when the bind() call executes.

	      Default value: 0, meaning that file permission (umask) is not ignored

	      This value can be changed at run time. See bind(2) for more information about creating domain sockets.

	      In a TruCluster environment, the value of this attribute must be the same on all member systems.

	      See kmem_debug.

	      A value that enables (1) or disables (0) behavior useful for debugging problems in kernel memory allocation.

	      Default value: 0

	      If  enabled  (1), each time the kernel memory allocator allocates or deallocates memory in the kernel memory pool, the system checks
	      whether the operation is performed correctly. If the kernel memory pool is in a corrupt state, the system crashes and provides  use-
	      ful  debugging  information.  This  attribute,  along  with  the kmem_audit_count, kmem_debug_size_mask, kmem_protected_kmempercent,
	      kmem_protected_lowat, kmem_protected_size, and a series of kmemhighwater_* attributes should be set only by or under  the  direction
	      of kernel software developers or support personnel.

	      See kmem_debug.

	      The maximum percentage of kernel virtual address space that is reserved for kernel memory allocator (malloc) memory.

	      Default value: Automatically set internally, depending on system memory size.

	      Minimum value: 0

	      Maximum value: 100

	      If  this value is too low, no space in map errors may occur and cause the system to hang. However, this situation indicates an unex-
	      pected problem that should be reported to your support representative.  Do not modify the  default  value  for  kmem_percent  unless
	      directed to do so by your support representative.

	      See kmem_debug.

	      See kmem_debug.

	      See kmem_debug.

	      See kmem_debug.

	      See kmem_debug.

	      The  percentage  of  memory  that  is reserved for the malloc component and used for kernel memory allocations that are less than or
	      equal to the page size (8 KB).

	      Default value: 0, which actually specifies 0.4 percent of available memory or 256 KB, whichever is smaller.

	      Minimum value: 1

	      Maximum value: 75

	      A heavy network load that results in dropped packets is the primary reason why you might want to	increase  the  kmemreserve_percent
	      value.  The  netstat  -d	-i  or the vmstat -M command shows you whether there are dropped packets. Increase the kmemreserve_percent
	      value in small increments until there are no entries in the fail_nowait column of the vmstat -M command's output display.

	      This value can be modified at run time. However, once the value has been increased, you cannot decrease it below 1  percent  at  run
	      time.  To  restore  the  default	setting  (which is calculated by the kernel), you must directly edit the /etc/sysconfigtab file to
	      remove or comment out the attribute and then reboot the system. This restriction will be removed in a future release.  (Under  ordi-
	      nary conditions, direct editing of the /etc/sysconfigtab file is a practice that is strongly discouraged.)

	      For internal use only. Do not modify this attribute. See dump_to_memory.

	      A  setting  that	enables  (1) or disables (0) a set of attribute values that improve performance for 32-MB systems.  This attribute
	      will soon be obsolete. Most kernel components now determine memory size directly and apply more sophisticated algorithms	to  deter-
	      mine defaults best suited for the system.

	      Default value: 1 if memory size is less than or equal to 32 MB and 0 if memory size is greater than 32 MB

	      Do not modify the default setting for this attribute unless instructed to do so by support personnel or by patch kit documentation.

	      The  full path to the directory where live dumps are written. This attribute allows you to write dumps generated while the system is
	      running to a directory other than the one where crash dumps are written.

	      Default value: /var/adm/crash (same directory as used for crash dumps)

	      Minimum string length: 1 (byte)

	      Maximum string length: 65 (bytes)

	      This value can be modified at run time.

	      A value that enables (1) or disables (0) zero compression of dumps that are generated while the system is still  running.  The  zero
	      compression process produces files that take longer to create but occupy less space on disk.

	      Default value: 1 (enabled)

	      This  value  can	be  modified  at run time. You might want to set this value to 1 if you consistently use tools, such as those from
	      third parties, that do not support compressed dump files or you want dumps created in a minimum amount of time. Because  the  system
	      is  still running while a live dump is being created, some of the data in a live dump may be inconsistent. The shorter creation time
	      may result in less data inconsistency.

	      See the Kernel Debugging and the System Administration manuals for more information about creating and working with dump files.

	      A value that enables (1) or disables (0) lock debugging. If enabled (1), the default value for the lockmode attribute is set to 4.

	      If you explicitly specify a value for the lockmode attribute, that value also causes lockdebug to be set or reset (overridden).  For
	      example,	if you set lockmodeto be 0, 1, 2, or 3, the value of lockdebug will be 0.  If you set lockmode to be 4, the value of lock-
	      debug will be 1.

	      Default value: 0 (disabled)

	      Used for internal debugging.

	      Default value: 0

	      Do not modify the default setting for this attribute unless instructed to do so by support personnel or by patch kit documentation.

	      The mode in which the lock package, simple (spin) or queued, is used  within  the  kernel.  (See	the  discussion  of  the  locktype
	      attribute  for information about the type of lock package used for different systems.) Mode settings, which apply to both lock pack-
	      ages, support different combinations of real-time (RT) kernel preemption, symmetric multiprocessing (SMP), and lock  debugging  with
	      lock  statistics:  Neither RT nor SMP is required.  In this case, the calls to the lock primitives are patched out completely.  Only
	      RT is required. In this case, the lock operations maintain a "preemption blocking" count.  Only SMP is required. In this	case,  the
	      lock  operations provide synchronization among multiple CPUs.  Both RT and SMP are required.  In this case, lock operations are per-
	      formed as described for both mode 1 and 2.  Both RT and SMP are required.  In this case, lock operations are as described  for  mode
	      3, with the addition of kernel lock debugging and statistics.

	      Default value: Assigned at boot time, depending on the values for the rt_preempt_opt, cpu_enable_mask, and lockdebug attributes, and
	      on whether multiple CPUs are able to be booted.

	      If you specify a value for lockmode (0-4), your setting both overrides the default setting and disables any  of  the  three  related
	      capabilities  that cannot be supported by the chosen set of lock primitives. For example, setting lockmode to 0, 1, 2, or 3 disables
	      kernel lock debugging and statistics, whether or not the lockdebug attribute was originally set to 1 (to enable kernel  lock  debug-
	      ging and statistics).

	      The  number of seconds that a CPU will wait on a lock. If a CPU cannot acquire a lock in the specified amount of time, a fatal error
	      occurs, and the system panics and issues a message that the lock time limit was exceeded.

	      Default value: 15 (seconds)

	      Do not modify the default setting for this attribute unless instructed to do so by support personnel or by patch kit instructions. A
	      0  value might cause boot failures on a multiprocessor system. Values larger than the default might hang the system instead of caus-
	      ing it to panic and reboot.

	      A value that specifies the type of locking package that the kernel software uses on the system. When the value is 0,  simple  (spin)
	      locking is used. When the value is 1, queued locking is used.

	      Default value: 1 on GS80, GS160, and GS320 systems; otherwise, 0.

	      Do not modify the default setting for this attribute unless instructed to do so by support personnel or by patch kit instructions.

	      The maximum number of bytes supported for a user's login name string. One byte may be equivalent to one character in many languages;
	      however, byte-to-character equivalence varies, depending on the user's default locale.

	      Default value: 12 (bytes)

	      Minimum value: 9

	      Maximum value: 64

	      In a TruCluster environment, the value of this attribute must be the same on all member systems.

	      The default 12-byte limit exists only for backward compatibility reasons. Increase login_name_max  to  64  to  enable  longer  login
	      names.

	      For internal use only. Do not modify this attribute. See compressed_dump.

	      For internal use only. Do not modify this attribute. See partial_dump.

	      The  depth  to  which  complex locks can be nested for a thread at one time.  The value of max_lock_per_thread is used for debugging
	      (when lockmode=4).

	      Default value: 16

	      Do not modify the default setting for this attribute unless instructed to do so by support personnel or by patch kit documentation.

	      Cluster member ID in the range of 0 to 63 that is set only by TruCluster software.

	      Default value: 0 (for standalone systems)

	      Minimum value: 0

	      Maximum value: 63

	      Reserved for future use by TruCluster software.

	      A kernel debugging value intended for internal use only.

	      A kernel debugging value intended for internal use only.

	      A kernel debugging value intended for internal use only.

	      A kernel debugging value intended for internal use only.

	      The size (in bytes) of the message buffer that is used to store boot log messages.

	      Default value: Set automatically, based on memory size.

	      Minimum value: 0 (bytes)

	      Maximum value: 1,048,576

	      You may need to increase this value on a large system that issues too many boot messages for the buffer to  hold	until  the  syslog
	      daemon  starts.  If  the buffer is too small, initial boot messages are not written to the system log and the beginning of the first
	      message that is written is likely to be truncated.

	      A value that is set and used internally to support a rolling upgrade operation in a TruCluster environment. Do not modify manually.

	      A value that is set and used internally to support a rolling upgrade operation in a TruCluster environment. Do not modify manually.

	      A value that changes the behavior of an internal system call.

	      Default value: 1 (on)

	      Do not modify the default setting for this attribute unless instructed to do so by support personnel or by patch kit  documentation.
	      Setting this value to off (0) has a negative impact on system performance.

	      A value that is set and used internally to support a rolling upgrade operation in a TruCluster environment. Do not modify manually.

	      A value that is set and used internally to support a rolling upgrade operation in a TruCluster environment. Do not modify manually.

	      A value that determines whether the system generates partial (1) or full (0) crash dumps.

	      Default value: 1 (partial dumps are created)

	      You can modify this attribute at run time. See the Kernel Debugging and the System Administration manuals for more information about
	      creating and working with dump files.

	      A value that controls how I/O requests are gathered when readv or writev operations are directed at a character device (not a  block
	      device).	 For example, when set to 65536, eight 8-KB buffers coalesce into one 64-KB buffer.  This improves the efficiency of data-
	      base operations.

	      Default value: 65,536

	      Do not modify the default setting for this attribute unless instructed to do so by support personnel or by patch kit documentation.

	      A value that controls whether kernel text can or cannot be replicated on multiple  CPUs  of  a  NUMA-enabled  system  (GS80,  GS160,
	      GS320).  When  the  value  is 1, replication of kernel text is enabled. When the value is 0, replication of kernel text is disabled.
	      This attribute is sometimes used by kernel developers when debugging software for NUMA-enabled systems; however,	the  attribute	is
	      not for general use. (The value must be 0 on non-NUMA systems and changing it to 0 on NUMA systems will degrade performance.)

	      Default value: 1, on a NUMA-enabled system; otherwise, 0.

	      Do not modify the default setting for this attribute unless instructed to do so by support personnel or by patch kit documentation.

	      A value that is set and used internally to support a rolling upgrade operation in a TruCluster environment. Do not modify manually.

	      A value that enables (1) or disables (0) real-time kernel preemption.

	      Default value: 0 (disabled)

	      If  real-time  kernel preemption is enabled (1): The default value for lockmode will be 1 on a single-CPU system or 3 on a multi-CPU
	      system.  However, if you explicitly specify certain lockmode values, you implicitly override the rt_preempt_opt value. For  example,
	      if you set lockmode to 0 or 2, you implicitly set rt_preempt_opt to 0, disabling real-time kernel preemption.  The default value for
	      ufs_lockholdmax will be 50. See sys_attrs_ufs(5) for information on ufs_lockholdmax.

	      A value that restores (1) or corrects (0) backward-compatible but incorrect behavior by the kernel's IEEE handler  with  respect	to
	      fast mode floating-point exception traps.

	      When  use_faulty_fpe_traps  is set to 0, the IEEE handler correctly returns a *_TRAP code for imprecise or invalid traps that cannot
	      be resolved and re-executed.

	      When use_faulty_fpe_traps is set to 1, the IEEE handler reverts to returning a *_FAULT code for faulty traps that  cannot  be  fixed
	      and re-executed. However, *_FAULT codes should be returned only when the trap's trigger PC and instructions can still be determined;
	      otherwise, re-execution cannot be completed.

	      See ieee(3) and the Alpha Architecture Reference Manual for more information on this topic.

	      Default value: 0 (correct return of *_TRAP code for faulty traps that cannot be resolved and re-executed)

	      It is strongly recommended that you do not modify the default value.

	      The CFG run-time points that are configurable from user mode. Setting this attribute to a particular value triggers kernel callbacks
	      that have been registered for the point corresponding to that value.

	      Default value: 45,000

	      Do not modify the default setting for this attribute unless instructed to do so by support personnel or by patch kit documentation.

SEE ALSO

       Commands: dxkerneltuner(8), sysconfig(8), sysconfigdb(8)

       Others: sys_attrs(5)

       System Configuration and Tuning

       System Administration

       Kernel Debugging

															      sys_attrs_generic(5)