1madv.so.1(1) User Commands madv.so.1(1)
2
6 madv.so.1 - madv library
7
9 /usr/lib/madv.so.1
10
13 The madv.so.1 shared object provides a means by which the VM advice can
14 be selectively configured for a launched process (or processes) and its
15 descendants. To enable madv.so.1, the following string needs to be
16 present in the environment (see ld.so.1(1)) along with one or more MADV
17 environment variables:
18 LD_PRELOAD=$LD_PRELOAD:madv.so.1
20
24 If the madv.so.1 shared object is specified in the LD_PRELOAD list, the
25 following environment variables are read by the madv shared object to
26 determine to which created process(es) to apply the specified advice.
27 MADV=advice MADV specifies the VM advice to use for all
29 heap, shared memory, and mmap regions in the
30 process address space. This
31 advice is applied to all created processes.
32 Values for advice correspond to values in
34 <sys/mman.h> used in madvise(3C) to specify
35 memory access patterns:
36 normal
37 random
38 sequential
39 access_lwp
40 access_many
41 access_default
42 MADVCFGFILE=config-file config-file is a text file which contains
45 one or more madv configuration entries of
46 the form:
47 exec-name exec-args:advice-opts
49 Advice specified in config-file takes prece‐
52 dence over that specified by the MADV envi‐
53 ronment variable. When MADVCFGFILE is not
54 set, advice is taken from file
55 /etc/madv.conf if it exists.
56 exec-name specifies the name of an applica‐
58 tion or executable. The corresponding advice
59 is set for newly created processes (see
60 getexecname(3C)) that match the first exec-
61 name found in the file.
62 exec-name can be a full pathname, a base
64 name, or a pattern string. See File Name
65 Generation in sh(1) for a discussion of pat‐
66 tern matching.
67 exec-args is an optionally specified pattern
69 string to match against arguments. Advice is
70 set only if exec-args is not specified or
71 occurs within the arguments to exec-name.
72 advice-opts is a comma-separated list speci‐
74 fying the advice for various memory
75 region(s):
76 madv=advice Applies to all heap,
78 shared memory, and mmap
79 regions in the process
80 address space.
81 heap=advice The heap is defined to
84 be the brk area (see
85 brk(2)). Applies to the
86 existing heap and for
87 any additional heap
88 memory allocated in the
89 future.
90 shm=advice Shared memory segments
93 ism=advice (see shmat(2)) attached
94 dism=advice using any flags, flag
95 SHM_SHARE_MMU, or flag
96 SHM_PAGEABLE respec‐
97 tively. Options ism and
98 dism take precedence
99 over option shm.
100 map=advice Mappings established
103 mapshared=advice through mmap(2) using
104 mapprivate=advice any flags, flag
105 mapanon=advice MAP_SHARED, flag
106 MAP_PRIVATE, or flag
107 MAP_ANON, respectively.
108 Options mapshared, map‐
109 private, and mapanon
110 take precedence over
111 option map. Option
112 mapanon takes prece‐
113 dence over mapshared
114 and mapprivate.
115 MADVERRFILE=pathname By default, error messages are logged via
119 syslog(3C) using level LOG_ERR and facility
120 LOG_USER. If MADVERRFILE contains a valid
121 pathname (such as /dev/stderr), error mes‐
122 sages will be logged there instead.
123
126 Example 1 Applying advice to all ISM segments
127 The following configuration applies advice to all ISM segments for
130 application /usr/bin/foo:
131 example$ LD_PRELOAD=$LD_PRELOAD:madv.so.1
134 example$ MADVCFGFILE=madvcfg
135 example$ export LD_PRELOAD MADVCFGFILE
136 example$ cat $MADVCFGFILE
137 /usr/bin/foo:ism=access_lwp
138 Example 2 Setting advice for all applications with exception
142 The following configuration sets advice for all applications with the
145 exception of ls.
146 example$ LD_PRELOAD=$LD_PRELOAD:madv.so.1
149 example$ MADV=access_many
150 example$ MADVCFGFILE=madvcfg
151 example$ export LD_PRELOAD MADV MADVCFGFILE
152 example$ cat $MADVCFGFILE
153 ls:
154 Example 3 Precedence rules (continuation from Example 2)
158 Because MADVCFGFILE takes precedence over MADV, specifying '*' (pattern
161 match all) for the exec-name of the last madv configuration entry would
162 be equivalent to setting MADV. The following is equivalent to example
163 2:
164 example$ LD_PRELOAD=$LD_PRELOAD:madv.so.1
167 example$ MADVCFGFILE=madvcfg
168 example$ export LD_PRELOAD MADVCFGFILE
169 example$ cat $MADVCFGFILE
170 ls:
171 *:madv=access_many
172 Example 4 Applying advice for different regions
176 The following configuration applies one type of advice for mmap regions
179 and different advice for heap and shared memory regions for a select
180 set of applications with exec names that begin with foo:
181 example$ LD_PRELOAD=$LD_PRELOAD:madv.so.1
184 example$ MADVCFGFILE=madvcfg
185 example$ export LD_PRELOAD MADVCFGFILE
186 example$ cat $MADVCFGFILE
187 foo*:madv=access_many,heap=sequential,shm=access_lwp
188 Example 5 Applying advice selectively
192 The following configuration applies advice for the heap of applications
195 beginning with ora that have ora1 as an argument:
196 example$ LD_PRELOAD=$LD_PRELOAD:madv.so.1
199 example$ MADVCFGFILE=madvcfg
200 example$ export LD_PRELOAD MADVCFGFILE
201 example$ cat $MADVCFGFILE
202 ora* ora1:heap=access_many
203
207 /etc/madv.conf Configuration file
208
211 See attributes(5) for descriptions of the following attributes:
212 ┌─────────────────────────────┬─────────────────────────────┐
217 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
218 ├─────────────────────────────┼─────────────────────────────┤
219 │Availability │SUNWesu (32-bit) │
220 ├─────────────────────────────┼─────────────────────────────┤
221 │ │SUNWesxu (64-bit) │
222 ├─────────────────────────────┼─────────────────────────────┤
223 │Interface Stability │Unstable │
224 └─────────────────────────────┴─────────────────────────────┘
225
227 cat(1), ld.so.1(1), proc(1), sh(1), brk(2), exec(2), fork(2), mmap(2),
228 memcntl(2), shmat(2), getexecname(3C), madvise(3C), syslog(3C),
229 proc(4), attributes(5)
230
232 The advice is inherited. A child process has the same advice as
233 its parent. On exec() (see exec(2)), the advice is set back to the
234 default system advice unless different advice has been configured via
235 the madv shared object.
236 Advice is only applied to mmap regions explicitly created by the user
239 program. Those regions established by the run-time linker or by system
240 libraries making direct system calls (for example, libthread alloca‐
241 tions for thread stacks) are not affected.
242SunOS 5.11 15 Feb 2002 madv.so.1(1)