op_alloc_counter.c File Reference

#include <stdlib.h>
#include <ctype.h>
#include <dirent.h>
#include "op_events.h"
#include "op_libiberty.h"

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Data Structures
struct	counter_arc_head
struct	counter_arc
Functions
static counter_arc_head *	build_counter_arc (struct op_event const *pev[], int nr_events)
static void	delete_counter_arc (counter_arc_head *ctr_arc, int nr_events)
static int	allocate_counter (counter_arc_head const ctr_arc, int max_depth, int depth, u32 allocated_mask, size_t counter_map)
static int	perfcounterdir (const struct dirent *entry)
static int	op_get_counter_mask (u32 *mask)
size_t *	map_event_to_counter (struct op_event const *pev[], int nr_events, op_cpu cpu_type)

Detailed Description

hardware counter allocation

You can have silliness here.

Remarks:: Copyright 2002 OProfile authors; Read the file COPYING

Author:: John Levon; Philippe Elie

Definition in file op_alloc_counter.c.

Function Documentation

static int allocate_counter	(	counter_arc_head const *	ctr_arc,
		int	max_depth,
		int	depth,
		u32	allocated_mask,
		size_t *	counter_map
	)			`[static]`

Parameters:

	ctr_arc	tree description, ctr_arc[i] is the i-th level of tree.
	max_depth	number of entry in array ctr_arc == depth of tree
	depth	current level we are exploring
	allocated_mask	current counter already allocated mask
	counter_map	array of counter number mapping, returned results go here

return non zero on succees, in this case counter_map is set to the counter mapping number.

Solution is searched through a simple backtracking exploring recursively all possible solution until one is found, prunning is done in O(1) by tracking a bitmask of already allocated counter. Walking through node is done in preorder left to right.

In case of extended events (required no phisical counters), the associated counter_map entry will be -1.

Possible improvment if neccessary: partition counters in class of counter, two counter belong to the same class if they allow exactly the same set of event. Now using a variant of the backtrack algo can works on class of counter rather on counter (this is not an improvment if each counter goes in it's own class)

Definition at line 126 of file op_alloc_counter.c.

References counter_arc::counter, list_entry, list_for_each, and list_head::next.

Referenced by map_event_to_counter().

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static counter_arc_head* build_counter_arc	(	struct op_event const *	pev[],
		int	nr_events
	)			`[static]`

Parameters:

	pev	an array of event
	nr_events	number of entry in pev

build an array of counter list allowed for each events counter_arc_head[i] is the list of allowed counter for pev[i] events The returned pointer is an array of nr_events entry

Definition at line 45 of file op_alloc_counter.c.

References counter_arc::counter, op_event::counter_mask, list_add_tail(), list_init(), counter_arc_head::next, counter_arc::next, and list_head::next.

Referenced by map_event_to_counter().

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static void delete_counter_arc	(	counter_arc_head *	ctr_arc,
		int	nr_events
	)			`[static]`

Parameters:

	ctr_arc	the array to deallocate
	nr_events	number of entry in array

deallocate all previously allocated resource by build_counter_arc()

Definition at line 85 of file op_alloc_counter.c.

References list_del(), list_entry, list_for_each_safe, counter_arc::next, and list_head::next.

Referenced by map_event_to_counter().

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size_t* map_event_to_counter	(	struct op_event const *	pev[],
		int	nr_events,
		op_cpu	cpu_type
	)

Parameters:

	pev	array of selected event we want to bind to counter
	nr_events	size of pev array
	cpu_type	cpu type

Try to calculate a binding between passed event in pev and counter number. The binding is returned in a size_t * where returned ptr[i] is the counter number bound to pev[i]

Definition at line 202 of file op_alloc_counter.c.

References allocate_counter(), build_counter_arc(), delete_counter_arc(), op_get_counter_mask(), op_get_cpu_type(), and op_get_nr_counters().

Referenced by oprof_start::alloc_selected_events(), do_test(), and resolve_events().

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