User Commands ppgsz(1)
NAME
ppgsz - set preferred page size for stack, heap, and/or
other anonymous segmentsSYNOPSIS
/usr/bin/ppgsz [-F] -o option[,option] cmd | -p pid...
DESCRIPTION
The ppgsz utility sets the preferred page size for stack,
heap, and/or other anonymous segments for the target process(es), that is, the launched cmd or the process(es) inthe pid list. ppgsz stops the target process(es) while
changing the page size. See memcntl(2). OPTIONS The following options are supported:-F Force. Sets the preferred page size
options(s) for target process(es) even if controlled by other process(es). Caution should be exercised when usingthe -F flag. See proc(1).
-o option[,option] The options are:
heap=size This option specifies the preferred page sizefor the heap of the tar-
get process(es). heap is defined to be the bss (uninitialized data) and the brk area that immediately follows the bss (see brk(2)). The preferred heap page size is set for the existingheap and for any addi-
tional heap memory allo-
cated in the future. See NOTES. stack=size This option specifies the preferred page size for the stack of the target process(es). The preferred stack page size is set for the existing stack and newly allocated parts of theSunOS 5.11 Last change: 23 Jan 2003 1
User Commands ppgsz(1)
stack as it expands. anon=size This option specifies the preferred page size for all existingMAP_PRIVATE anonymous
segments of the target process(es), other than heap and stack, which are large enough to fit at least one aligned page of the specified size. For the segments that are large enough, the preferred page size is set starting at thefirst size-aligned
address in the segment. The anon preferred pagesize is not appliedto MAP_PRIVATE anonymous
segments created in thefuture. See MAP_ANON in
mmap(2). Anonymous memory refersto MAP_PRIVATE pages
that are not directly associated with a file in some filesystem. Theppgsz command uses
memcntl(2) to set the preferred page size for anonymous segments. SeeMC_HAT_ADVISE in
memcntl(2). At least one of the above options must be specified. size must be a supported page size (see pagesize(1)) or 0, in which case the system will select an appropriate page size. See memcntl(2). size defaults to bytes and can be specified in octal (0), decimal, or hexadecimal (0x). The numeric value can be qualified with K, M, G, or T tospecify Kilobytes, Megabytes, Giga-
bytes, or Terabytes, respectively.SunOS 5.11 Last change: 23 Jan 2003 2
User Commands ppgsz(1)
4194304, 0x400000, 4096K, 0x1000K, and 4M are different ways to specify 4 Megabytes.-p pid Sets the preferred page size option(s)
for the target process(es) in theprocess-id (pid) list following the -p
option. The pid list can also consist of names in the /proc directory. Onlythe process owner or the super-user is
permitted to set page size.cmd is interpreted if -p is not speci-
fied. ppgsz launches cmd and applies
page size option(s) to the new pro-
cess. The heap and stack preferred page sizes are inherited. Child process(es) created (see fork(2)) from the launched process or the target process(es) in the pid list afterppgsz completes will inherit the pre-
ferred heap and stack page sizes. The preferred page sizes of all segments are set back to the default system page size on exec(2) (see getpagesize(3C)). The preferred page size for all other anonymous segments is not inherited by children of the launched or target process(es).EXAMPLES
Example 1 Setting the preferred heap and stack page size The following example sets the preferred heap page size to4M and the preferred stack page size to 512K for all ora-
owned processes running commands that begin with ora:example% ppgsz -o heap=4M,stack=512K -p `pgrep -u ora '^ora'`
Example 2 Setting the preferred anonymous page sizeThe following example sets the preferred page size of exist-
ing qualifying anonymous segments to 512k for process IDSunOS 5.11 Last change: 23 Jan 2003 3
User Commands ppgsz(1)
953:example% ppgsz -o anon=512k -p 953
EXIT STATUS If cmd is specified and successfully invoked (see exec(2)),the exit status of ppgsz will be the exit status of cmd.
Otherwise, ppgsz will exit with one of the following values:
0 Successfully set preferred page size(s) for processes in the pid list.125 An error occurred in ppgsz. Errors include: invalid
argument, invalid page size(s) specified, and failure to set preferred page size(s) for one or more processes in the pid list or cmd. 126 cmd was found but could not be invoked. 127 cmd could not be found. FILES /proc/* Process files./usr/lib/ld/map.bssalign A template link-editor mapfile
for aligning bss (see NOTES).ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:SunOS 5.11 Last change: 23 Jan 2003 4
User Commands ppgsz(1)
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| ____________________________|_____________________________|_
| Availability | system/extended-system- |
| | utilities (32-bit) |
| | SUNWesxu (64-bit) |
|_____________________________|_____________________________|
| Interface Stability | Committed ||_____________________________|_____________________________|
SEE ALSO
ld(1), mpss.so.1(1), pagesize(1), pgrep(1), pmap(1), proc(1), brk(2), exec(2), fork(2), memcntl(2), mmap(2), sbrk(2), getpagesize(3C), proc(4), attributes(5) Linker and Libraries Guide NOTES Due to resource constraints, the setting of the preferred page size does not necessarily guarantee that the target process(es) will get the preferred page size. Use pmap(1) to view the actual heap and stack page sizes of the targetprocess(es) (see pmap -s option).
Large pages are required to be mapped at addresses that are multiples of the size of the large page. Given that the heap is typically not large page aligned, the starting portions of the heap (below the first large page aligned address) are mapped with the system memory page size. See getpagesize(3C). To provide a heap that will be mapped with a large pagesize, an application can be built using a link-editor
(ld(1)) mapfile containing the bss segment declaration directive. Refer to the section Mapfile Option in the Linker and Libraries Guide for more details of this directive and the template mapfile provided in /usr/lib/ld/map.bssalign. Users are cautioned that an alignment specification may bemachine-specific and may lose its benefit on different
hardware platforms. A more flexible means of requesting the most optimal underlying page size may evolve in future releases. mpss.so.1(1), a preloadable shared object, can also be used to set the preferred stack and/or heap page sizes.SunOS 5.11 Last change: 23 Jan 2003 5