3
global a global variable
4
"(" . string_var . ")" string concatentation
5
string_var = sprint(123) convert integer to string
6
printf("%u", var) variables are untyped, but types should be specified while printing
7
thread_indent(1) / thread_indent(-1) Indenting the output
9
if () ... else if () ... else ... conditionals
10
if (string_var == "test") ... string conditionals
12
while (i < 5) ... loops
13
for (i = 0; i < 5; i++) ... for
14
function add(a,b) { return a + b; } functions
16
global b[128] array (or actually the map) with space reserved for 128 tupples
17
bloabl b%[128] ring-buffer style array (the old elements will be overriden when running out of space)
18
b["name", 1]++ incrementing an element of array defined by two variables of which one is string and another integer
19
if (["name", 1] in b) check if element is in array
20
delete(["name", 1]) detelete element
21
foreach (x = [a,b] in foo) { ... } iterate over elements
22
foreach (x = [a,b] in foo+ limit 5) { } sort by value (inc) and iterate over first 5 elements
23
foreach (x = [a-,b] in foo) { } sort by first key (desc) and iterate
25
var <<< latency aggregates (variable collects statistical information which can be requested later wish special functions)
26
@avg(var), @min, @max, @sum, @count statististics on aggregated variable [ per processor? ]
27
@hist_linear(var,min,max,step) generate a histogram
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@hist_log(var) logarithmic histogram
29
delete var clean statistics
31
print(var|histogram|$var|$$vars) print the stuff
35
probe probe_spec { ... } Probes are entry points of script
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probe probe_spec if (cond) { ... } Conditional probe (but it will not save performance, at least as of 2015.08)
37
$var the variable defined in the probe context (i.e. local variable or parameter in kernel function)
38
* stap -L 'kernel.function("sys_open")' Get all variables at specified probe (both uprobes & krpobes)
39
* stap -L 'kernel.function("*@net/socket.c")' Show all existing probes for the specified pattern (both uprobes & kprobes)
40
$$vars is used for a pretty-printed listing of all local variables in scope: print($$vars)
41
@defined($var) checks if variable is define in the probe scope: if (@defined($size)) { ... }
42
@cast($ptr) casts pointer to its type
43
$1 $2 $3 ... command line parameters
47
- begin The startup of the systemtap session.
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- end The end of the systemtap session.
49
- timer.profile A timer that fires periodically on every CPU.
50
- timer.ms(200) A timer that fires every 200 milliseconds.
51
- syscall.close The syscall
52
- syscall.close.return The return from the close system call.
53
- kernel.function("sys_open") The entry to the function named sys_open in the kernel (only kernel, not modules)
54
- kernel.function("*@net/socket.c") All functions in net/socket.c
55
- module("ext3").statement(0xdeadbeef) The addressed instruction in the ext3 filesystem driver.
56
- process("~/a.out").statement("*@main.c:200") Line 200 of the a.out program (will not resolve symbols/code from shared libraries).
57
- process("~/libpcilib.so.2").function("*@kmem.c") The same way the shared library may be probed
58
- ... .function("*").return Probe at return statement of the specified function
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- ... .function("*").label("fail") Probe at the specified label
60
- procfs("status").read A process trying to read a synthetic file.
61
- perf.hw.cache_misses A particular number of CPU cache misses have occurred.
66
- target() The process pid specified with -x PID parameter
70
- tid() The id of the current thread.
71
- pid() The process (task group) id of the current thread.
72
- uid() The id of the current user.
73
- execname() The name of the current process.
74
- cpu() The current cpu number.
75
- gettimeofday_us() Number of microseconds since epoch (_s, _ms as well)
76
- get_cycles() Snapshot of hardware cycle counter.
77
- pp() A string describing the probe point being currently handled.
78
- ppfunc() If known, the the function name in which this probe was placed.
79
- print_backtrace() If possible, print a kernel backtrace.
80
- print_ubacktrace() If possible, print a user-space backtrace.
84
/usr/share/systemtap/tapset All functions defined there can be used directly
85
stap -I <dir> ... Specify additional directory with tapsets
89
stap -g ... Disabled by default, should run in guru mode
90
* Do not dereference pointers that are not known or testable valid.
91
* Do not call any kernel routine that may cause a sleep or fault.
92
* Prevent recursion, where your embedded C function calls a routine that may be the subject of a probe.
93
* If locking of a data structure is necessary, use a trylock type call to attempt to take the lock. If that fails, give up, do not block.
95
function test_func:int (pid:long) The emdedded C function should define types of all variables
96
%{ ... %} Embedded C code is indicated with "%{"
added
removed
Analysis/instrumentation/systap/probes.txt
