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process.c
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process.c
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/*
* Copyright 2010 Red Hat Inc.
* Author: Michal Schmidt
* License: GPLv2
*/
#include <assert.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include "process.h"
#include "timespan.h"
#include "lat_translator.h"
#include "lattop.h"
static void la_clear(struct latency_account *la)
{
la->total = la->max = la->count = 0;
}
static void la_init(struct latency_account *la, uint64_t delay)
{
la->total = delay;
la->max = delay;
la->count = 1;
}
static void la_add_delay(struct latency_account *la, uint64_t delay)
{
la->total += delay;
if (la->max < delay)
la->max = delay;
la->count++;
}
static void la_sum_delay(struct latency_account *la,
const struct latency_account *other)
{
la->total += other->total;
if (la->max < other->max)
la->max = other->max;
la->count += other->count;
}
static int compare_by_max_latency(const void *p1, const void *p2)
{
struct bt2la *b1 = *(struct bt2la**)p1;
struct bt2la *b2 = *(struct bt2la**)p2;
if (b1->la.max < b2->la.max)
return 1;
else if (b1->la.max > b2->la.max)
return -1;
else
return 0;
}
static int compare_by_total_latency(const void *p1, const void *p2)
{
struct bt2la *b1 = *(struct bt2la**)p1;
struct bt2la *b2 = *(struct bt2la**)p2;
if (b1->la.total < b2->la.total)
return 1;
else if (b1->la.total > b2->la.total)
return -1;
else
return 0;
}
void process_dump(struct process *p)
{
struct rb_node *node;
struct bt2la **array;
char sym_bt[1000], commpidtid[52], total[32], max[32];
unsigned n = 0;
static int (*const sort_func[_NR_SORT_BY])(const void *, const void *) = {
[SORT_BY_MAX_LATENCY] = compare_by_max_latency,
[SORT_BY_TOTAL_LATENCY] = compare_by_total_latency,
[SORT_BY_PID] = compare_by_max_latency, /* sorting by pid makes no sense within a process */
};
format_timespan(total, 32, p->summarized.total/1000, 3);
format_timespan(max, 32, p->summarized.max/1000, 3);
if (p->pid != p->tid)
snprintf(commpidtid, sizeof(commpidtid), "%s (%d, thread %d)", p->comm, p->pid, p->tid);
else
snprintf(commpidtid, sizeof(commpidtid), "%s (%d)", p->comm, p->pid);
printf("%-51s Max:%8s Total:%8s\n", commpidtid, max, total);
array = alloca(sizeof(struct bt2la*) * p->bt2la_count);
for (node = rb_first(&p->bt2la_map); node; node = rb_next(node)) {
struct bt2la *bt2la = rb_entry(node, struct bt2la, rb_node);
array[n++] = bt2la;
}
assert(n == p->bt2la_count);
qsort(array, n, sizeof(struct bt2la*), sort_func[arg_sort]);
for (n = 0; n < p->bt2la_count; n++) {
struct bt2la *bt2la = array[!arg_reverse ? n : p->bt2la_count - n - 1];
double percentage = (bt2la->la.total*100.0)/p->summarized.total;
const char *translation;
bt_save_symbolic(&bt2la->bt, sym_bt+1, sizeof(sym_bt)-1);
translation = lat_translator_translate_stack(sym_bt+1);
if (!translation) {
size_t end = strnlen(sym_bt+1, 49);
sym_bt[0] = '[';
/* this is safe, because sym_bt array is way larger than our strnlen limit above */
sym_bt[end+1] = ']';
sym_bt[end+2] = '\0';
}
format_timespan(total, 32, bt2la->la.total/1000, 3);
format_timespan(max, 32, bt2la->la.max/1000, 3);
printf(" %-51s Max:%8s %5.1f%%\n", translation ?: sym_bt, max, percentage);
}
}
void process_summarize(struct process *p)
{
struct rb_node *node;
la_clear(&p->summarized);
for (node = rb_first(&p->bt2la_map); node; node = rb_next(node)) {
struct bt2la *bt2la = rb_entry(node, struct bt2la, rb_node);
la_sum_delay(&p->summarized, &bt2la->la);
}
}
/*
* Search the rb-tree
* Returns the node with the same back_trace if it exists.
* If not, returns NULL, and sets the 'parent' and 'link' pointers to where
* the newly created node should be put.
*/
static struct bt2la *rb_search_bt2la(struct process *process,
struct back_trace *bt,
struct rb_node **pparent,
struct rb_node ***plink)
{
struct rb_node **p = &process->bt2la_map.rb_node;
struct rb_node *parent = NULL;
struct bt2la *bt2la;
int cmp;
while (*p) {
parent = *p;
bt2la = rb_entry(parent, struct bt2la, rb_node);
cmp = bt_compare(bt, &bt2la->bt);
if (cmp < 0)
p = &(*p)->rb_left;
else if (cmp > 0)
p = &(*p)->rb_right;
else
return bt2la;
}
*pparent = parent;
*plink = p;
return NULL;
}
void process_suffer_latency(struct process *p, uint64_t delay,
struct back_trace *bt)
{
struct bt2la *item;
struct rb_node *parent;
struct rb_node **link;
item = rb_search_bt2la(p, bt, &parent, &link);
if (item) {
la_add_delay(&item->la, delay);
return;
}
item = malloc(sizeof(struct bt2la));
item->bt = *bt;
la_init(&item->la, delay);
rb_link_node(&item->rb_node, parent, link);
rb_insert_color(&item->rb_node, &p->bt2la_map);
p->bt2la_count++;
}
struct process *process_new(pid_t pid, pid_t tid, const char comm[16])
{
struct process *p;
p = malloc(sizeof(struct process));
if (!p)
return NULL;
p->bt2la_map = RB_ROOT;
p->pid = pid;
p->tid = tid;
strcpy(p->comm, comm);
la_clear(&p->summarized);
p->bt2la_count = 0;
return p;
}
/*
* rb_erase would be an overkill. There's no need to rebalance,
* since we're destroying the whole tree.
*/
static void process_delete_rbtree(struct rb_node *n)
{
struct bt2la *item;
if (!n)
return;
process_delete_rbtree(n->rb_left);
process_delete_rbtree(n->rb_right);
item = rb_entry(n, struct bt2la, rb_node);
free(item);
}
void process_fini(struct process *p)
{
process_delete_rbtree(p->bt2la_map.rb_node);
}