Tribblix: manual page: pmadvise.1

PMADVISE(1) User Commands 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_default
purge

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 a particular 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_PURGE
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 $$
100666: tcsh
00010000 312K r-x-- /usr/bin/tcsh
0006C000 48K rwx-- /usr/bin/tcsh
00078000 536K rwx-- [ heap ]
FF100000 856K r-x-- /lib/libc.so.1
FF1E6000 32K rwx-- /lib/libc.so.1
FF1EE000 8K rwx-- /lib/libc.so.1
FF230000 168K r-x-- /lib/libcurses.so.1
FF26A000 32K rwx-- /lib/libcurses.so.1
FF272000 8K rwx-- /lib/libcurses.so.1
FF280000 576K r-x-- /lib/libnsl.so.1
FF310000 40K rwx-- /lib/libnsl.so.1
FF31A000 24K rwx-- /lib/libnsl.so.1
FF364000 8K rwxs- [ anon ]
FF370000 48K r-x-- /lib/libsocket.so.1
FF38C000 8K rwx-- /lib/libsocket.so.1
FF3A0000 8K r-x-- /platform/sun4u-us3/lib/libc_psr.so.1
FF3B0000 176K r-x-- /lib/ld.so.1
FF3EC000 8K rwx-- /lib/ld.so.1
FF3EE000 8K rwx-- /lib/ld.so.1
FFBE6000 104K rw--- [ stack ]
%
% pmadvise -o 78000=access_lwp $$

%

Example 2: Using the -v Option

The following example displays verbose output from pmadvise:

% pmadvise -o heap=access_lwp,stack=access_default -v $$
1720: -sh
00010000 88K r-x-- /sbin/sh
00036000 8K rwx-- /sbin/sh
00038000 16K rwx-- [ heap ] <= access_lwp
FF250000 24K r-x-- /lib/libgen.so.1
FF266000 8K rwx-- /lib/libgen.so.1
FF272000 8K rwxs- [ anon ]
FF280000 840K r-x-- /lib/libc.so.1
FF362000 32K rwx-- /lib/libc.so.1
FF36A000 16K rwx-- /lib/libc.so.1
FF380000 8K r-x-- /platform/sun4u-us3/lib/libc_psr.so.1
FF390000 64K rwx-- [ anon ]
FF3B0000 168K r-x-- /lib/ld.so.1
FF3EA000 8K rwx-- /lib/ld.so.1
FF3EC000 8K rwx-- /lib/ld.so.1
FFBFE000 8K rw--- [ stack ] <= access_default

EXIT STATUS

The following exit values are returned:

0
Successful completion.

non-zero
An error occurred.

FILES

/proc/*
Process files

ATTRIBUTES

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

+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | See below. |
+--------------------+-----------------+

The command syntax is Evolving. The output formats are Unstable.