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man pages section 1: User Commands

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Updated: Thursday, June 13, 2019
 
 

pmadvise(1)

Name

pmadvise - applies advice about memory to a process

Synopsis

pmadvise -o option[,option] [-F] [-l] [-v] pid...

Description

pmadvise applies advice about how memory is used in the specified process using madvise(3C).

pmadvise allows users to apply advice to a specific sub-range at a specific instant in time. pmadvise differs from madv.so.1(1) in that madv.so.1(1) applies the advice throughout execution of the target program to all segments of a specified type.

Options

The following options are supported:

–F

Force by grabbing the target process even if another process has control.

You should exercise caution when using the –F option. See proc(1).

–l

Show unresolved dynamic linker map names.

–o

Specify advice to apply in the following form:


private=advice
shared=advice
heap=advice
stack=advice
address[:length]=advice

where the advice can be one of the following:


normal
random
sequential
willneed
dontneed
free
access_lwp
access_many
access_many_pset
access_default

An address and length can be given to specify a subrange to apply the advice. The address should be hexadecimal and the length should be in bytes by default.

If length is not specified and the starting address refers to the start of a segment, the advice is applied to that segment. length can be qualified by K, M, G, T, P, or E to specify kilobytes, megabytes, gigabytes, terabytes, or exabytes respectively as the unit of measure.

–v

Print verbose output. Display output as pmap(1) does, showing what advice is being applied where. This can be useful when the advice is being applied to a named region (for example, private, shared, and so forth) to get feedback on exactly where the advice is being applied.

pmadvise tries to process all legal options. If an illegal address range is specified, an error message is printed and the offending option is skipped. pmadvise quits without processing any options and prints a usage message when there is a syntax error.

If conflicting advice is given on a region, the order of precedence is from most specific advice to least, that is, most general. In other words, advice specified for an explicit address range takes precedence over advice for heap and stack which in turn takes precedence over advice for private and shared memory.

Moreover, the advice in each of the following groups are mutually exclusive from the other advice within the same group:


MADV_NORMAL, MADV_RANDOM, MADV_SEQUENTIAL
MADV_WILLNEED, MADV_DONTNEED, MADV_FREE
MADV_ACCESS_DEFAULT, MADV_ACCESS_LWP, MADV_ACCESS_MANY

Operands

The following operands are supported:

pid

Process ID.

Examples

Example 1 Applying Advice to a Segment at Specified Address

The following example applies advice to a segment at a specified address:


% pmap $$ | grep heap
00000001AEC8C000    8K rw-----  [ heap ]
%
% pmadvise -o 78000=access_lwp $$

%
Example 2 Using the –v Option

The following example displays verbose output from pmadvise. In the interest of brevity, some output has been elided.

 
% pmadvise -o heap=access_lwp,stack=access_default -v $$
0000000100000000 1728K r-x----  [ text ] /usr/bin/sh
00000001001B0000   56K r-x----  [ text ] /usr/bin/sh
00000001002BE000    8K rwx----  [ data ] /usr/bin/sh
00000001002C0000   64K rwx----  [ data ] /usr/bin/sh
00000001002D0000   16K rwx----  [ data ] /usr/bin/sh
0000000100300000   24K rw-----  [ bss ] /usr/bin/sh
0000000EEBFC4000    8K rw-----  [ heap ]        <= access_lwp
0007FCB434C00000 2176K r-x----  [ text ] /lib/sparcv9/libc.so.1
...
0007FCB435000000  704K r-x----  [ text ] /lib/sparcv9/libm.so.2
...
0007FCB435200000  256K r-x----  [ text ] /lib/sparcv9/ld.so.1
...
0007FCB435370000  128K rw-----  [ anon ]
...
FFFFFCFCE72A0000   64K rw-----  [ stack ]       <= access_default
FFFFFCFCE72B0000   40K rw-----  [ stack ]       <= access_default

Exit Status

The following exit values are returned:

0

Successful completion.

non-zero

An error occurred.

Files

/proc/*

Process files

/usr/prob/lib/*

proc tools support files

Attributes

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE
ATTRIBUTE VALUE
Availability
system/core-os
Interface Stability
See below.

The command syntax is Committed. The output formats are Uncommitted.

See Also

madv.so.1(1), pmap(1), proc(1), madvise(3C), attributes(7)