/usr/share/systemtap/tapset
Edit: /usr/share/systemtap/tapset/indent.stp (4590B)
/*
* The indent tapset provides functions to generate indented lines for
* nested kinds of trace messages. Each line contains a relative
* timestamp, and the process name / pid. The timestamp is as per
* provided by the __indent_timestamp function, which by default
* measures microseconds.
*
*/
@__private30 global _indent_counters, _indent_timestamps
@__private30 function _generic_indent_depth:long (idx, delta)
{
# pre-increment for positive delta and post-decrement for negative delta
x = _indent_counters[idx] + (delta > 0 ? delta : 0)
_indent_counters[idx] += delta
return (x>0 ? x-1 : 0)
}
@__private30 function _generic_indent (idx, desc, delta)
{
ts = __indent_timestamp ()
if (! _indent_counters[idx]) _indent_timestamps[idx] = ts
depth = _generic_indent_depth(idx, delta)
return sprintf("%6d %s:%-*s", (ts - _indent_timestamps[idx]), desc, depth, "")
}
/**
* sfunction thread_indent - returns an amount of space with the current task information
*
* @delta: the amount of space added/removed for each call
*
* Description: This function returns a string with appropriate
* indentation for a thread. Call it with a small positive or
* matching negative delta. If this is the real outermost,
* initial level of indentation, then the function resets the
* relative timestamp base to zero. The timestamp is as per
* provided by the __indent_timestamp function, which by default
* measures microseconds.
*/
function thread_indent:string (delta:long)
{
return _generic_indent (tid(), sprintf("%s(%d)", execname(), tid()), delta)
}
/**
* sfunction thread_indent_depth - returns the nested-depth of the current task
*
* @delta: the amount of depth added/removed for each call
*
* Description: This function returns an integer equal to the nested
* function-call depth starting from the outermost initial level. This function
* is useful for saving space (consumed by whitespace) in traces with long
* nested function calls. Use this function in a similar fashion to
* thread_indent(), i.e., in call-probe, use thread_indent_depth(1) and in
* return-probe, use thread_indent_depth(-1)
*/
function thread_indent_depth:long (delta:long)
{
return _generic_indent_depth (tid(), delta)
}
/**
* sfunction indent - returns an amount of space to indent
*
* @delta: the amount of space added/removed for each call
*
* Description: This function returns a string with appropriate
* indentation. Call it with a small positive or matching negative
* delta. Unlike the thread_indent function, the indent does not
* track individual indent values on a per thread basis.
*/
function indent:string (delta:long){
return _generic_indent(-1, "", delta)
}
/**
* sfunction indent_depth - returns the global nested-depth
*
* @delta: the amount of depth added/removed for each call
*
* Description: This function returns a number for appropriate indentation,
* similar to indent(). Call it with a small positive or matching negative
* delta. Unlike the thread_indent_depth function, the indent does not track
* individual indent values on a per thread basis.
*/
function indent_depth:long (delta:long)
{
return _generic_indent_depth (-1, delta)
}
/* The following example uses thread_indent() to trace the functions
* called in the drivers/usb/core kernel source. It prints a relative
* timestamp and the name and ID of the current process, followed by
* the appropriate indent and the function name. Note that
* 'char' swapper(0) indicates the kernel is running in interrupt
* context and there is no valid current process.
*
* probe kernel.function("*@drivers/usb/core/*") {
* printf("%s -> %s\n, thread_indent(1), probefunc())
* }
* probe kernel.function("*@drivers/usb/core/*").return {
* printf("%s <- %s\n", thread_indent(-1), probefunc())
* }
*
* //This prints:
* 0 swapper(0): -> usb_hcd_irq
* 8 swapper(0): <- usb_hcd_irq
* 0 swapper(0): -> usb_hcd_irq
* 10 swapper(0): -> usb_hcd_giveback_urb
* 16 swapper(0): -> urb_unlink
* 22 swapper(0): <- usb_unlink
* 29 swapper(0): -> usb_free_urb
* 35 swapper(0): <- usb_hcd_urb
* 39 swapper(0): <- usb_hcd_giveback_urb
* 45 swapper(0): <- usb_hcd_irq
* 0 usb-storage(1338): -> usb_submit_urb
* 6 usb-storage(1338): -> usb_hcd_submit_urb
* 12 usb-storage(1338): -> usb_get_urb
* 18 usb-storage(1338): <- usb_get_urb
* 25 usb-storage(1338): <- usb_hcd_submit_urb
* 29 usb-storage(1338): -> usb_submit_urb
* 0 swapper(0): -> usb_hcd_irq
* 7 swapper(0): <- usb_hcd_irq
*/