RE: [PATCH 1/1] Reduce synchronize_rcu() waiting time

[Zhuo, Qiuxu]

Hi Rezki,

Thank you so much for sharing this super cool parser! ;-)
It will help me/us to speed up parsing the tracing logs. 

-Qiuxu

> From: Uladzislau Rezki <urezki@xxxxxxxxx>
> Sent: Wednesday, March 22, 2023 2:50 PM
> To: Zhuo, Qiuxu <qiuxu.zhuo@xxxxxxxxx>
> Cc: Uladzislau Rezki <urezki@xxxxxxxxx>; Paul E . McKenney
> <paulmck@xxxxxxxxxx>; RCU <rcu@xxxxxxxxxxxxxxx>;
> quic_neeraju@xxxxxxxxxxx; Boqun Feng <boqun.feng@xxxxxxxxx>; Joel
> Fernandes <joel@xxxxxxxxxxxxxxxxx>; LKML <linux-kernel@xxxxxxxxxxxxxxx>;
> Oleksiy Avramchenko <oleksiy.avramchenko@xxxxxxxx>; Steven Rostedt
> <rostedt@xxxxxxxxxxx>; Frederic Weisbecker <frederic@xxxxxxxxxx>
> Subject: Re: [PATCH 1/1] Reduce synchronize_rcu() waiting time
> 
> On Wed, Mar 22, 2023 at 01:49:50AM +0000, Zhuo, Qiuxu wrote:
> > Hi Rezki,
> >
> > > From: Uladzislau Rezki <urezki@xxxxxxxxx>
> > > Sent: Tuesday, March 21, 2023 11:16 PM [...]
> > > >
> > > >
> > > > If possible, may I know the steps, commands, and related
> > > > parameters to
> > > produce the results above?
> > > > Thank you!
> > > >
> > > Build the kernel with CONFIG_RCU_TRACE configuration. Update your
> > > "set_event"
> > > file with appropriate traces:
> > >
> > > <snip>
> > > XQ-DQ54:/sys/kernel/tracing # echo rcu:rcu_batch_start
> > > rcu:rcu_batch_end rcu:rcu_invoke_callback > set_event
> > >
> > > XQ-DQ54:/sys/kernel/tracing # cat set_event rcu:rcu_batch_start
> > > rcu:rcu_invoke_callback rcu:rcu_batch_end
> > > XQ-DQ54:/sys/kernel/tracing # <snip>
> > >
> > > Collect traces as much as you want: XQ-DQ54:/sys/kernel/tracing #
> > > echo 1 > tracing_on; sleep 10; echo 0 > tracing_on Next problem is
> > > how to parse it. Of
> >
> > Thanks for the detailed steps to collect the related testing results.
> >
> > > course you will not be able to parse megabytes of traces. For that
> > > purpose i use a special C trace parser.
> > > If you need an example please let me know i can show here.
> > >
> >
> > Yes, your example parser should save me from a huge amount of traces.
> > ;-) Thanks so much for your sharing.
> >
> See below the C program. It is ugly but it does what you need. Please have a
> look at main function:
> 
> <snip>
> #include <stdio.h>
> #include <stdlib.h>
> #include <stdbool.h>
> #include <ctype.h>
> #include <string.h>
> 
> /*
>  * Splay-tree implementation to store data: key,value
>  * See https://en.wikipedia.org/wiki/Splay_tree
>  */
> #define offsetof(TYPE, MEMBER)	((unsigned long)&((TYPE *)0)-
> >MEMBER)
> #define container_of(ptr, type, member)			\
> ({
> 			\
> 	void *__mptr = (void *)(ptr);					\
> 	((type *)(__mptr - offsetof(type, member)));	\
> })
> 
> #define SP_INIT_NODE(node)
> 			\
> 	((node)->left = (node)->right = (node)->parent = NULL)
> 
> struct splay_node {
> 	struct splay_node *left;
> 	struct splay_node *right;
> 	struct splay_node *parent;
> 	unsigned long val;
> };
> 
> struct splay_root {
> 	struct splay_node *sp_root;
> };
> 
> static inline void
> set_parent(struct splay_node *n, struct splay_node *p) {
> 	if (n)
> 		n->parent = p;
> }
> 
> static inline void
> change_child(struct splay_node *p,
> 	struct splay_node *old, struct splay_node *new) {
> 	if (p) {
> 		if (p->left == old)
> 			p->left = new;
> 		else
> 			p->right = new;
> 	}
> }
> 
> /*
>  * left rotation of node (r), (rc) is (r)'s right child  */ static inline struct
> splay_node * left_pivot(struct splay_node *r) {
> 	struct splay_node *rc;
> 
> 	/*
> 	 * set (rc) to be the new root
> 	 */
> 	rc = r->right;
> 
> 	/*
> 	 * point parent to new left/right child
> 	 */
> 	rc->parent = r->parent;
> 
> 	/*
> 	 * change child of the p->parent.
> 	 */
> 	change_child(r->parent, r, rc);
> 
> 	/*
> 	 * set (r)'s right child to be (rc)'s left child
> 	 */
> 	r->right = rc->left;
> 
> 	/*
> 	 * change parent of rc's left child
> 	 */
> 	set_parent(rc->left, r);
> 
> 	/*
> 	 * set new parent of rotated node
> 	 */
> 	r->parent = rc;
> 
> 	/*
> 	 * set (rc)'s left child to be (r)
> 	 */
> 	rc->left = r;
> 
> 	/*
> 	 * return the new root
> 	 */
> 	return rc;
> }
> 
> /*
>  * right rotation of node (r), (lc) is (r)'s left child  */ static inline struct
> splay_node * right_pivot(struct splay_node *r) {
> 	struct splay_node *lc;
> 
> 	/*
> 	 * set (lc) to be the new root
> 	 */
> 	lc = r->left;
> 
> 	/*
> 	 * point parent to new left/right child
> 	 */
> 	lc->parent = r->parent;
> 
> 	/*
> 	 * change child of the p->parent.
> 	 */
> 	change_child(r->parent, r, lc);
> 
> 	/*
> 	 * set (r)'s left child to be (lc)'s right child
> 	 */
> 	r->left = lc->right;
> 
> 	/*
> 	 * change parent of lc's right child
> 	 */
> 	set_parent(lc->right, r);
> 
> 	/*
> 	 * set new parent of rotated node
> 	 */
> 	r->parent = lc;
> 
> 	/*
> 	 * set (lc)'s right child to be (r)
> 	 */
> 	lc->right = r;
> 
> 	/*
> 	 * return the new root
> 	 */
> 	return lc;
> }
> 
> static struct splay_node *
> top_down_splay(unsigned long vstart,
> 	struct splay_node *root, struct splay_root *sp_root) {
> 	/*
> 	 * During the splitting process two temporary trees are formed.
> 	 * "l" contains all keys less than the search key/vstart and "r"
> 	 * contains all keys greater than the search key/vstart.
> 	 */
> 	struct splay_node head, *ltree_max, *rtree_max;
> 	struct splay_node *ltree_prev, *rtree_prev;
> 
> 	if (root == NULL)
> 		return NULL;
> 
> 	SP_INIT_NODE(&head);
> 	ltree_max = rtree_max = &head;
> 	ltree_prev = rtree_prev = NULL;
> 
> 	while (1) {
> 		if (vstart < root->val && root->left) {
> 			if (vstart < root->left->val) {
> 				root = right_pivot(root);
> 
> 				if (root->left == NULL)
> 					break;
> 			}
> 
> 			/*
> 			 * Build right subtree.
> 			 */
> 			rtree_max->left = root;
> 			rtree_max->left->parent = rtree_prev;
> 			rtree_max = rtree_max->left;
> 			rtree_prev = root;
> 			root = root->left;
> 		} else if (vstart > root->val && root->right) {
> 			if (vstart > root->right->val) {
> 				root = left_pivot(root);
> 
> 				if (root->right == NULL)
> 					break;
> 			}
> 
> 			/*
> 			 * Build left subtree.
> 			 */
> 			ltree_max->right = root;
> 			ltree_max->right->parent = ltree_prev;
> 			ltree_max = ltree_max->right;
> 			ltree_prev = root;
> 			root = root->right;
> 		} else {
> 			break;
> 		}
> 	}
> 
> 	/*
> 	 * Assemble the tree.
> 	 */
> 	ltree_max->right = root->left;
> 	rtree_max->left = root->right;
> 	root->left = head.right;
> 	root->right = head.left;
> 
> 	set_parent(ltree_max->right, ltree_max);
> 	set_parent(rtree_max->left, rtree_max);
> 	set_parent(root->left, root);
> 	set_parent(root->right, root);
> 	root->parent = NULL;
> 
> 	/*
> 	 * Set new root. Please note it might be the same.
> 	 */
> 	sp_root->sp_root = root;
> 	return sp_root->sp_root;
> }
> 
> struct splay_node *
> splay_search(unsigned long key, struct splay_root *root) {
> 	struct splay_node *n;
> 
> 	n = top_down_splay(key, root->sp_root, root);
> 	if (n && n->val == key)
> 		return n;
> 
> 	return NULL;
> }
> 
> static bool
> splay_insert(struct splay_node *n, struct splay_root *sp_root) {
> 	struct splay_node *r;
> 
> 	SP_INIT_NODE(n);
> 
> 	r = top_down_splay(n->val, sp_root->sp_root, sp_root);
> 	if (r == NULL) {
> 		/* First element in the tree */
> 		sp_root->sp_root = n;
> 		return false;
> 	}
> 
> 	if (n->val < r->val) {
> 		n->left = r->left;
> 		n->right = r;
> 
> 		set_parent(r->left, n);
> 		r->parent = n;
> 		r->left = NULL;
> 	} else if (n->val > r->val) {
> 		n->right = r->right;
> 		n->left = r;
> 
> 		set_parent(r->right, n);
> 		r->parent = n;
> 		r->right = NULL;
> 	} else {
> 		/*
> 		 * Same, indicate as not success insertion.
> 		 */
> 		return false;
> 	}
> 
> 	sp_root->sp_root = n;
> 	return true;
> }
> 
> static bool
> splay_delete_init(struct splay_node *n, struct splay_root *sp_root) {
> 	struct splay_node *subtree[2];
> 	unsigned long val = n->val;
> 
> 	/* 1. Splay the node to the root. */
> 	n = top_down_splay(n->val, sp_root->sp_root, sp_root);
> 	if (n == NULL || n->val != val)
> 		return false;
> 
> 	/* 2. Save left/right sub-trees. */
> 	subtree[0] = n->left;
> 	subtree[1] = n->right;
> 
> 	/* 3. Now remove the node. */
> 	SP_INIT_NODE(n);
> 
> 	if (subtree[0]) {
> 		/* 4. Splay the largest node in left sub-tree to the root. */
> 		top_down_splay(val, subtree[0], sp_root);
> 
> 		/* 5. Attach the right sub-tree as the right child of the left
> sub-tree. */
> 		sp_root->sp_root->right = subtree[1];
> 
> 		/* 6. Update the parent of right sub-tree */
> 		set_parent(subtree[1], sp_root->sp_root);
> 	} else {
> 		/* 7. Left sub-tree is NULL, just point to right one. */
> 		sp_root->sp_root = subtree[1];
> 	}
> 
> 	/* 8. Set parent of root node to NULL. */
> 	if (sp_root->sp_root)
> 		sp_root->sp_root->parent = NULL;
> 
> 	return true;
> }
> 
> static FILE *
> open_perf_script_file(const char *path)
> {
> 	FILE *f = NULL;
> 
> 	if (path == NULL)
> 		goto out;
> 
> 	f = fopen(path, "r");
> 	if (!f)
> 		goto out;
> 
> out:
> 	return f;
> }
> 
> static int
> get_one_line(FILE *file, char *buf, size_t len) {
> 	int i = 0;
> 
> 	memset(buf, '\0', len);
> 
> 	for (i = 0; i < len - 1; i++) {
> 		int c = fgetc(file);
> 
> 		if (c == EOF)
> 			return EOF;
> 
> 		if (c == '\n')
> 			break;
> 
> 		if (c != '\r')
> 			buf[i] = c;
> 	}
> 
> 	return i;
> }
> 
> static int
> read_string_till_string(char *buf, char *out, size_t out_len, char *in, size_t
> in_len) {
> 	int i, j;
> 
> 	memset(out, '\0', out_len);
> 
> 	for (i = 0; i < out_len; i++) {
> 		if (buf[i] != in[0]) {
> 			out[i] = buf[i];
> 			continue;
> 		}
> 
> 		for (j = 0; j < in_len; j++) {
> 			if (buf[i + j] != in[j])
> 				break;
> 		}
> 
> 		/* Found. */
> 		if (j == in_len)
> 			return 1;
> 	}
> 
> 	return 0;
> }
> 
> /*
>  * find pattern is  "something [003] 8640.034785: something"
>  */
> static inline void
> get_cpu_sec_usec_in_string(const char *s, int *cpu, int *sec, int *usec) {
> 	char usec_buf[32] = {'\0'};
> 	char sec_buf[32] = {'\0'};
> 	char cpu_buf[32] = {'\0'};
> 	bool found_sec = false;
> 	bool found_usec = false;
> 	bool found_cpu = false;
> 	int i, j, dot;
> 
> 	*cpu = *sec = *usec = -1;
> 
> 	for (i = 0, j = 0; s[i] != '\0'; i++) {
> 		if (s[i] == '.') {
> 			dot = i++;
> 
> 			/* take microseconds */
> 			for (j = 0; j < sizeof(usec_buf); j++) {
> 				if (isdigit(s[i])) {
> 					usec_buf[j] = s[i];
> 				} else {
> 					if (s[i] == ':' && j > 0)
> 						found_usec = true;
> 					else
> 						found_usec = false;
> 
> 					/* Terminate here. */
> 					break;
> 				}
> 
> 				i++;
> 			}
> 
> 			if (found_usec) {
> 				/* roll back */
> 				while (s[i] != ' ' && i > 0)
> 					i--;
> 
> 				/* take seconds */
> 				for (j = 0; j < sizeof(sec_buf); j++) {
> 					if (isdigit(s[++i])) {
> 						sec_buf[j] = s[i];
> 					} else {
> 						if (s[i] == '.' && j > 0)
> 							found_sec = true;
> 						else
> 							found_sec = false;
> 
> 						/* Terminate here. */
> 						break;
> 					}
> 				}
> 			}
> 
> 			if (found_sec && found_usec) {
> 				/* roll back */
> 				while (s[i] != '[' && i > 0)
> 					i--;
> 
> 				/* take seconds */
> 				for (j = 0; j < sizeof(cpu_buf); j++) {
> 					if (isdigit(s[++i])) {
> 						cpu_buf[j] = s[i];
> 					} else {
> 						if (s[i] == ']' && j > 0)
> 							found_cpu = true;
> 						else
> 							found_cpu = false;
> 
> 						/* Terminate here. */
> 						break;
> 					}
> 				}
> 
> 				if (found_cpu && found_sec && found_usec)
> {
> 					*sec = atoi(sec_buf);
> 					*usec = atoi(usec_buf);
> 					*cpu = atoi(cpu_buf);
> 					return;
> 				}
> 			}
> 
> 			/*
> 			 * Check next dot pattern.
> 			 */
> 			found_sec = false;
> 			found_usec = false;
> 			found_cpu = false;
> 			i = dot;
> 		}
> 	}
> }
> 
> /*
>  * find pattern is  "something comm=foo android thr1 pid=123 something"
>  */
> static inline int
> get_comm_pid_in_string(const char *buf, char *comm, ssize_t len, int *pid) {
> 	char *sc, *sp;
> 	int rv, i;
> 
> 	memset(comm, '\0', len);
> 
> 	sc = strstr(buf, "comm=");
> 	if (sc)
> 		sp = strstr(sc, " pid=");
> 
> 	if (!sc || !sp)
> 		return -1;
> 
> 	for (i = 0, sc += 5; sc != sp; i++) {
> 		if (i < len) {
> 			if (*sc == ' ')
> 				comm[i] = '-';
> 			else
> 				comm[i] = *sc;
> 
> 			sc++;
> 		}
> 	}
> 
> 	/* Read pid. */
> 	rv = sscanf(sp, " pid=%d", pid);
> 	if (rv != 1)
> 		return -1;
> 
> 	return 1;
> }
> 
> static void
> perf_script_softirq_delay(FILE *file, int delay_usec) {
> 	char buf[4096] = { '\0' };
> 	char buf_1[4096] = { '\0' };
> 	long offset;
> 	char *s;
> 	int rv;
> 
> 	while (1) {
> 		rv = get_one_line(file, buf, sizeof(buf));
> 		offset = ftell(file);
> 
> 		if (rv != EOF) {
> 			s = strstr(buf, "irq:softirq_raise:");
> 			if (s) {
> 				char extra[512] = {'\0'};
> 				int sec_0, usec_0;
> 				int sec_1, usec_1;
> 				int handle_vector;
> 				int rise_vector;
> 				int cpu_0;
> 				int cpu_1;
> 
> 				/*
> 				 * swapper     0    [000]  6010.619854:
> irq:softirq_raise: vec=7 [action=SCHED]
> 				 * android.bg  3052 [001]  6000.076212:
> irq:softirq_entry: vec=9 [action=RCU]
> 				 */
> 				(void) sscanf(s, "%s vec=%d", extra,
> &rise_vector);
> 				get_cpu_sec_usec_in_string(buf, &cpu_0,
> &sec_0, &usec_0);
> 
> 				while (1) {
> 					rv = get_one_line(file, buf_1,
> sizeof(buf_1));
> 					if (rv == EOF)
> 						break;
> 
> 					s = strstr(buf_1, "irq:softirq_entry:");
> 					if (s) {
> 						(void) sscanf(s, "%s vec=%d",
> extra, &handle_vector);
> 
> 	get_cpu_sec_usec_in_string(buf_1, &cpu_1, &sec_1, &usec_1);
> 
> 						if (cpu_0 == cpu_1 &&
> rise_vector == handle_vector) {
> 							int delta_time_usec =
> (sec_1 - sec_0) * 1000000 + (usec_1 - usec_0);
> 
> 							if (delta_time_usec >
> delay_usec)
> 								fprintf(stdout,
> "{\n%s\n%s\n} diff %d usec\n", buf, buf_1, delta_time_usec);
> 							break;
> 						}
> 					}
> 				}
> 			}
> 
> 			rv = fseek(file, offset, SEEK_SET);
> 			if (rv)
> 				fprintf(stdout, "fseek error !!!\n");
> 		} else {
> 			break;
> 		}
> 	}
> }
> 
> static void
> perf_script_softirq_duration(FILE *file, int duration_usec) {
> 	char buf[4096] = { '\0' };
> 	char buf_1[4096] = { '\0' };
> 	long offset;
> 	char *s;
> 	int rv;
> 
> 	while (1) {
> 		rv = get_one_line(file, buf, sizeof(buf));
> 		offset = ftell(file);
> 
> 		if (rv != EOF) {
> 			s = strstr(buf, "irq:softirq_entry:");
> 			if (s) {
> 				char extra[512] = {'\0'};
> 				int sec_0, usec_0;
> 				int sec_1, usec_1;
> 				int handle_vector;
> 				int rise_vector;
> 				int cpu_0;
> 				int cpu_1;
> 
> 				/*
> 				 * swapper     0    [000]  6010.619854:
> irq:softirq_entry: vec=7 [action=SCHED]
> 				 * android.bg  3052 [001]  6000.076212:
> irq:softirq_exit: vec=9 [action=RCU]
> 				 */
> 				(void) sscanf(s, "%s vec=%d", extra,
> &rise_vector);
> 				get_cpu_sec_usec_in_string(buf, &cpu_0,
> &sec_0, &usec_0);
> 
> 				while (1) {
> 					rv = get_one_line(file, buf_1,
> sizeof(buf_1));
> 					if (rv == EOF)
> 						break;
> 
> 					s = strstr(buf_1, "irq:softirq_exit:");
> 					if (s) {
> 						(void) sscanf(s, "%s vec=%d",
> extra, &handle_vector);
> 
> 	get_cpu_sec_usec_in_string(buf_1, &cpu_1, &sec_1, &usec_1);
> 
> 						if (cpu_0 == cpu_1 &&
> rise_vector == handle_vector) {
> 							int delta_time_usec =
> (sec_1 - sec_0) * 1000000 + (usec_1 - usec_0);
> 
> 							if (delta_time_usec >
> duration_usec)
> 								fprintf(stdout,
> "{\n%s\n%s\n} diff %d usec\n", buf, buf_1, delta_time_usec);
> 							break;
> 						}
> 					}
> 				}
> 			}
> 
> 			rv = fseek(file, offset, SEEK_SET);
> 			if (rv)
> 				fprintf(stdout, "fseek error !!!\n");
> 		} else {
> 			break;
> 		}
> 	}
> }
> 
> static void
> perf_script_hardirq_duration(FILE *file, int duration_msec) {
> 	char buf[4096] = { '\0' };
> 	char buf_1[4096] = { '\0' };
> 	long offset;
> 	char *s;
> 	int rv;
> 
> 	while (1) {
> 		rv = get_one_line(file, buf, sizeof(buf));
> 		offset = ftell(file);
> 
> 		if (rv != EOF) {
> 			s = strstr(buf, "irq:irq_handler_entry:");
> 			if (s) {
> 				char extra[512] = {'\0'};
> 				int sec_0, usec_0;
> 				int sec_1, usec_1;
> 				int handle_vector;
> 				int rise_vector;
> 				int cpu_0;
> 				int cpu_1;
> 
> 				/*
> 				 * swapper     0 [002]  6205.804133:
> irq:irq_handler_entry: irq=11 name=arch_timer
> 				 * swapper     0 [002]  6205.804228:
> irq:irq_handler_exit: irq=11 ret=handled
> 				 */
> 				(void) sscanf(s, "%s irq=%d", extra,
> &rise_vector);
> 				get_cpu_sec_usec_in_string(buf, &cpu_0,
> &sec_0, &usec_0);
> 
> 				while (1) {
> 					rv = get_one_line(file, buf_1,
> sizeof(buf_1));
> 					if (rv == EOF)
> 						break;
> 
> 					s = strstr(buf_1,
> "irq:irq_handler_exit:");
> 					if (s) {
> 						(void) sscanf(s, "%s irq=%d",
> extra, &handle_vector);
> 
> 	get_cpu_sec_usec_in_string(buf_1, &cpu_1, &sec_1, &usec_1);
> 
> 						if (cpu_0 == cpu_1 &&
> rise_vector == handle_vector) {
> 							int delta_time_usec =
> (sec_1 - sec_0) * 1000000 + (usec_1 - usec_0);
> 
> 							if (delta_time_usec >
> duration_msec)
> 								fprintf(stdout,
> "{\n%s\n%s\n} diff %d usec\n", buf, buf_1, delta_time_usec);
> 							break;
> 						}
> 					}
> 				}
> 			}
> 
> 			rv = fseek(file, offset, SEEK_SET);
> 			if (rv)
> 				fprintf(stdout, "fseek error !!!\n");
> 		} else {
> 			break;
> 		}
> 	}
> }
> 
> struct irq_stat {
> 	int irq;
> 	int count;
> 	char irq_name[512];
> 
> 	int min_interval;
> 	int max_interval;
> 	int avg_interval;
> 
> 	unsigned int time_stamp_usec;
> 	struct splay_node node;
> };
> 
> static struct irq_stat *
> new_irq_node_init(int irq, char *irq_name) {
> 	struct irq_stat *n = calloc(1, sizeof(*n));
> 
> 	if (n) {
> 		n->irq = irq;
> 		(void) strncpy(n->irq_name, irq_name, sizeof(n->irq_name));
> 		n->node.val = irq;
> 	}
> 
> 	return n;
> }
> 
> static void
> perf_script_hardirq_stat(FILE *file)
> {
> 	struct splay_root sproot = { NULL };
> 	struct irq_stat *node;
> 	char buf[4096] = { '\0' };
> 	char extra[256] = {'\0'};
> 	char irq_name[256] = {'\0'};
> 	unsigned int time_stamp_usec;
> 	int cpu, sec, usec;
> 	int rv, irq;
> 	char *s;
> 
> 	while (1) {
> 		rv = get_one_line(file, buf, sizeof(buf));
> 		if (rv == EOF)
> 			break;
> 
> 		 s = strstr(buf, "irq:irq_handler_entry:");
> 		 if (s == NULL)
> 			 continue;
> 
> 		 /*
> 		  * format is as follow one:
> 		  * sleep  1418 [003]  8780.957112:
> irq:irq_handler_entry: irq=11 name=arch_timer
> 		  */
> 		 rv = sscanf(s, "%s irq=%d name=%s", extra, &irq, irq_name);
> 	 	 if (rv != 3)
> 	 		 continue;
> 
> 		 get_cpu_sec_usec_in_string(buf, &cpu, &sec, &usec);
> 		 time_stamp_usec = (sec * 1000000) + usec;
> 
> 		 if (sproot.sp_root == NULL) {
> 			 node = new_irq_node_init(irq, irq_name);
> 			 if (node)
> 				 splay_insert(&node->node, &sproot);
> 		 }
> 
> 		 top_down_splay(irq, sproot.sp_root, &sproot);
> 		 node = container_of(sproot.sp_root, struct irq_stat, node);
> 
> 		 /* Found the entry in the tree. */
> 		 if (node->irq == irq) {
> 			 if (node->time_stamp_usec) {
> 				 unsigned int delta = time_stamp_usec -
> node->time_stamp_usec;
> 
> 				 if (delta < node->min_interval || !node-
> >min_interval)
> 					 node->min_interval = delta;
> 
> 				 if (delta > node->max_interval)
> 					 node->max_interval = delta;
> 
> 				 node->avg_interval += delta;
> 			 }
> 
> 			 /* Save the last time for this IRQ entry. */
> 			 node->time_stamp_usec = time_stamp_usec;
> 		 } else {
> 			 /* Allocate a new record and place it to the tree. */
> 			 node = new_irq_node_init(irq, irq_name);
> 			 if (node)
> 				 splay_insert(&node->node, &sproot);
> 
> 		 }
> 
> 		 /* Update the timestamp for this entry. */
> 		 node->time_stamp_usec = time_stamp_usec;
> 		 node->count++;
> 	}
> 
> 	/* Dump the tree. */
> 	while (sproot.sp_root) {
> 		node = container_of(sproot.sp_root, struct irq_stat, node);
> 
> 		fprintf(stdout, "irq: %5d name: %30s count: %7d, min: %10d,
> max: %10d, avg: %10d\n",
> 				node->irq, node->irq_name, node->count,
> 				node->min_interval, node->max_interval,
> node->avg_interval / node->count);
> 
> 		splay_delete_init(&node->node, &sproot);
> 		free(node);
> 	}
> 
> 	fprintf(stdout, "\tRun './a.out ./perf.script | sort -nk 6' to sort by
> column 6.\n"); }
> 
> struct sched_waking {
> 	unsigned int wakeup_nr;
> 	char comm[4096];
> 	int pid;
> 
> 	int min;
> 	int max;
> 	int avg;
> 
> 	unsigned int time_stamp_usec;
> 	struct splay_node node;
> };
> 
> static struct sched_waking *
> new_sched_waking_node_init(int pid, char *comm) {
> 	struct sched_waking *n = calloc(1, sizeof(*n));
> 
> 	if (n) {
> 		n->pid = pid;
> 		(void) strncpy(n->comm, comm, sizeof(n->comm));
> 		n->node.val = pid;
> 	}
> 
> 	return n;
> }
> 
> /*
>  * How many times a task is awaken + min/max/avg stat.
>  */
> static void
> perf_script_sched_waking_stat(const char *name, FILE *file, const char
> *script) {
> 	struct splay_root sroot = { NULL };
> 	struct sched_waking *n;
> 	char buf[4096] = { '\0' };
> 	char comm[256] = {'\0'};
> 	unsigned int time_stamp_usec;
> 	unsigned int total_waking = 0;
> 	int cpu, sec, usec;
> 	int rv, pid;
> 	char *s;
> 
> 	while (1) {
> 		rv = get_one_line(file, buf, sizeof(buf));
> 		if (rv == EOF)
> 			break;
> 		/*
> 		 * format is as follow one:
> 		 * foo[1] 7521 [002] 10.431216: sched_waking: comm=tr
> pid=2 prio=120 target_cpu=006
> 		 */
> 		s = strstr(buf, "sched_waking:");
> 		if (s == NULL)
> 			continue;
> 
> 		rv = get_comm_pid_in_string(s, comm, sizeof(comm), &pid);
> 		if (rv < 0) {
> 			printf("ERROR: skip entry...\n");
> 			continue;
> 		}
> 
> 		get_cpu_sec_usec_in_string(buf, &cpu, &sec, &usec);
> 		time_stamp_usec = (sec * 1000000) + usec;
> 
> 		if (sroot.sp_root == NULL) {
> 			n = new_sched_waking_node_init(pid, comm);
> 			if (n)
> 				splay_insert(&n->node, &sroot);
> 		}
> 
> 		top_down_splay(pid, sroot.sp_root, &sroot);
> 		n = container_of(sroot.sp_root, struct sched_waking, node);
> 
> 		/* Found the entry in the tree. */
> 		if (n->pid == pid) {
> 			if (n->time_stamp_usec) {
> 				unsigned int delta = time_stamp_usec - n-
> >time_stamp_usec;
> 
> 				if (delta < n->min || !n->min)
> 					n->min = delta;
> 
> 				if (delta > n->max)
> 					n->max = delta;
> 
> 				n->avg += delta;
> 			}
> 
> 			/* Save the last time for this wake-up entry. */
> 			n->time_stamp_usec = time_stamp_usec;
> 		} else {
> 			/* Allocate a new record and place it to the tree. */
> 			n = new_sched_waking_node_init(pid, comm);
> 			if (n)
> 				splay_insert(&n->node, &sroot);
> 		}
> 
> 		/* Update the timestamp for this entry. */
> 		n->time_stamp_usec = time_stamp_usec;
> 		n->wakeup_nr++;
> 	}
> 
> 	/* Dump the Splay-tree. */
> 	while (sroot.sp_root) {
> 		n = container_of(sroot.sp_root, struct sched_waking, node);
> 		fprintf(stdout, "name: %30s pid: %10d woken-
> up %5d\tinterval: min %5d\tmax %5d\tavg %5d\n",
> 			n->comm, n->pid, n->wakeup_nr,
> 			n->min, n->max, n->avg / n->wakeup_nr);
> 
> 		total_waking += n->wakeup_nr;
> 		splay_delete_init(&n->node, &sroot);
> 		free(n);
> 	}
> 
> 	fprintf(stdout, "=== Total: %u ===\n", total_waking);
> 	fprintf(stdout, "\tRun './%s %s | sort -nk 6' to sort by column 6.\n",
> name, script); }
> 
> /*
>  * Latency of try_to_wake_up path + select a CPU + placing a task into run-
> queue.
>  */
> static void
> perf_script_sched_wakeup_latency(const char *name, FILE *file, const char
> *script) {
> 	struct splay_root sroot = { NULL };
> 	struct splay_node *node;
> 	struct sched_waking *n;
> 	char buf[4096] = { '\0' };
> 	char comm[256] = {'\0'};
> 	unsigned int time_stamp_usec;
> 	unsigned int wakeup_latency_usec;
> 	unsigned int total_waking = 0;
> 	int cpu, sec, usec;
> 	int rv, pid;
> 	char *sched_waking_wakeup;
> 	bool sched_waking_event;
> 
> 	while (1) {
> 		rv = get_one_line(file, buf, sizeof(buf));
> 		if (rv == EOF)
> 			break;
> 
> 		/*
> 		 * format is as follow one:
> 		 * foo[1] 7521 [002] 10.431216: sched_waking: comm=tr
> pid=2 prio=120 target_cpu=006
> 		 */
> 		sched_waking_wakeup = strstr(buf, "sched_waking:");
> 		sched_waking_event = !!sched_waking_wakeup;
> 
> 		if (!sched_waking_event) {
> 			/*
> 			 * format is as follow one:
> 			 * foo[1] 7521 [002] 10.431216: sched_wakeup:
> comm=tr pid=2 prio=120 target_cpu=006
> 			 */
> 			sched_waking_wakeup = strstr(buf,
> "sched_wakeup:");
> 			if (sched_waking_wakeup == NULL)
> 				continue;
> 		}
> 
> 		rv = get_comm_pid_in_string(sched_waking_wakeup, comm,
> sizeof(comm), &pid);
> 		if (rv < 0) {
> 			printf("ERROR: skip entry...\n");
> 			continue;
> 		}
> 
> 		get_cpu_sec_usec_in_string(buf, &cpu, &sec, &usec);
> 		time_stamp_usec = (sec * 1000000) + usec;
> 
> 		/*
> 		 * Let's check if it exists, if so update it
> 		 * otherwise create a new node and insert.
> 		 */
> 		if (sched_waking_event) {
> 			node = top_down_splay(pid, sroot.sp_root, &sroot);
> 			if (node == NULL) {
> 				n = new_sched_waking_node_init(pid,
> comm);
> 				splay_insert(&n->node, &sroot);
> 			} else {
> 				n = container_of(node, struct sched_waking,
> node);
> 				if (n->pid != pid) {
> 					n = new_sched_waking_node_init(pid,
> comm);
> 					splay_insert(&n->node, &sroot);
> 				}
> 			}
> 
> 			n->time_stamp_usec = time_stamp_usec;
> 			continue;
> 		}
> 
> 		node = top_down_splay(pid, sroot.sp_root, &sroot);
> 		if (node == NULL) {
> 			fprintf(stdout, "error: no sched_waking event for %d
> pid yet.\n", pid);
> 			continue;
> 		}
> 
> 		n = container_of(node, struct sched_waking, node);
> 		if (n->pid != pid) {
> 			fprintf(stdout, "error: sched_wakeup event does not
> match with any sched_waking event.\n");
> 			continue;
> 		}
> 
> 		wakeup_latency_usec = time_stamp_usec - n-
> >time_stamp_usec;
> 
> 		if (wakeup_latency_usec < n->min || !n->min)
> 			n->min = wakeup_latency_usec;
> 
> 		if (wakeup_latency_usec > n->max)
> 			n->max = wakeup_latency_usec;
> 
> 		if (n->avg + wakeup_latency_usec < n->avg)
> 			fprintf(stdout, "error: counter is overflowed...\n");
> 
> 		fprintf(stdout, "%s: %d wake-up latency: %u waken on %d
> CPU\n", comm, pid, wakeup_latency_usec, cpu);
> 
> 		n->avg += wakeup_latency_usec;
> 		n->wakeup_nr++;
> 	}
> 
> 	/* Dump the Splay-tree. */
> 	while (sroot.sp_root) {
> 		n = container_of(sroot.sp_root, struct sched_waking, node);
> 		/* fprintf(stdout, "name: %30s pid: %10d woken-
> up %5d\twakeup-latency: min %5d\tmax %5d\tavg %5d\n", */
> 		/* 	n->comm, n->pid, n->wakeup_nr, */
> 		/* 	n->min, n->max, n->avg / n->wakeup_nr); */
> 
> 		total_waking += n->wakeup_nr;
> 		splay_delete_init(&n->node, &sroot);
> 		free(n);
> 	}
> 
> 	/* fprintf(stdout, "=== Total: %u ===\n", total_waking); */
> 	/* fprintf(stdout, "\tRun '%s %s | sort -nk 6' to sort by column 6.\n",
> name, script); */ }
> 
> 
> /*
>  * Requires:
>  *   rcu:rcu_batch_start
>  *   rcu:rcu_invoke_callback
>  *   rcu:rcu_batch_end
>  */
> static void
> perf_script_synchronize_rcu_latency(const char *name, FILE *file, const char
> *script) {
> 	char buf[4096] = { '\0' };
> 	char buf_1[4096] = { '\0' };
> 	long offset;
> 	char *s;
> 	int rv;
> 
> 	while (1) {
> 		rv = get_one_line(file, buf, sizeof(buf));
> 		offset = ftell(file);
> 
> 		if (rv != EOF) {
> 			s = strstr(buf, "rcu_batch_start:");
> 			if (s) {
> 				int delta_time_usec;
> 				int sec_0, usec_0;
> 				int sec_1, usec_1;
> 				int pid_0, pid_1;
> 				int extra;
> 
> 				/*
> 				 * rcuop/5-58      [007] d..1.  6111.808748:
> rcu_batch_start: rcu_preempt CBs=23 bl=10
> 				 */
> 				(void) sscanf(buf, "%*[^0-9]%d-%d", &pid_0,
> &pid_0);
> 				get_cpu_sec_usec_in_string(buf, &extra,
> &sec_0, &usec_0);
> 
> 				while (1) {
> 					rv = get_one_line(file, buf_1,
> sizeof(buf_1));
> 					if (rv == EOF)
> 						break;
> 
> 					/* Do not care what a string format is
> on this step. */
> 					(void) sscanf(buf, "%*[^0-9]%d-%d",
> &pid_1, &pid_1);
> 
> 					/*
> 					 * rcuop/4-51      [007] d..1.
> 6111.816758: rcu_batch_end: rcu_preempt CBs-invoked=1 idle=....
> 					 */
> 					s = strstr(buf_1, "rcu_batch_end:");
> 					if (s && pid_0 == pid_1)
> 						break;
> 
> 					/*
> 					 * rcuop/1-29      [005] .....
> 6111.808745: rcu_invoke_callback: rcu_preempt rhp=0000000093881c60
> func=file_free_rcu.cfi_jt
> 					 */
> 					s = strstr(buf_1,
> "rcu_invoke_callback:");
> 					if (!s || pid_0 != pid_1)
> 						continue;
> 
> 					s = strstr(buf_1,
> "wakeme_after_rcu");
> 					if (s) {
> 
> 	get_cpu_sec_usec_in_string(buf_1, &extra, &sec_1, &usec_1);
> 						delta_time_usec = (sec_1 -
> sec_0) * 1000000 + (usec_1 - usec_0);
> 						fprintf(stdout, "{\n%s\n%s\n}
> latency %d usec\n", buf, buf_1, delta_time_usec);
> 						break;
> 					}
> 				}
> 			}
> 
> 			rv = fseek(file, offset, SEEK_SET);
> 			if (rv)
> 				fprintf(stdout, "fseek error !!!\n");
> 		} else {
> 			break;
> 		}
> 	}
> 
> }
> 
> int main(int argc, char **argv)
> {
> 	FILE *file;
> 
> 	file = open_perf_script_file(argv[1]);
> 	if (file == NULL) {
> 		fprintf(stdout, "%s:%d failed: specify a perf script file\n",
> __func__, __LINE__);
> 		exit(-1);
> 	}
> 
> 	/* perf_script_softirq_delay(file, 1000); */
> 	/* perf_script_softirq_duration(file, 500); */
> 	/* perf_script_hardirq_duration(file, 500); */
> 	/* perf_script_hardirq_stat(file); */
> 	/* perf_script_sched_waking_stat(argv[0], file, argv[1]); */
> 	/* perf_script_sched_wakeup_latency(argv[0], file, argv[1]); */
> 	perf_script_synchronize_rcu_latency(argv[0], file, argv[1]);
> 
> 	return 0;
> }
> <snip>
> 
> Running it as "./a.out app_launch_rcu_trace.txt" will produce below results:

Thanks for the usage example.

> <snip>
> ...
> {
>     <...>-29      [001] d..1. 21950.145313: rcu_batch_start: rcu_preempt
> CBs=3613 bl=28
>     <...>-29      [001] ..... 21950.152583: rcu_invoke_callback: rcu_preempt
> rhp=000000008f162ca8 func=wakeme_after_rcu.cfi_jt
> } latency 7270 usec
> {
>     rcuop/5-58      [005] d..1. 21951.352767: rcu_batch_start: rcu_preempt
> CBs=3 bl=10
>     rcuop/5-58      [005] ..... 21951.352768: rcu_invoke_callback: rcu_preempt
> rhp=00000000b995fac1 func=wakeme_after_rcu.cfi_jt
> } latency 1 usec
> {
>     rcuop/6-65      [007] d..1. 21951.804768: rcu_batch_start: rcu_preempt
> CBs=5 bl=10
>     rcuop/6-65      [007] ..... 21951.804769: rcu_invoke_callback: rcu_preempt
> rhp=00000000b995fac1 func=wakeme_after_rcu.cfi_jt
> } latency 1 usec
> {
>     rcuop/7-72      [006] d..1. 21951.884774: rcu_batch_start: rcu_preempt
> CBs=3517 bl=27
>     rcuop/7-72      [006] ..... 21951.885979: rcu_invoke_callback: rcu_preempt
> rhp=000000005119eccc func=wakeme_after_rcu.cfi_jt
> } latency 1205 usec
> {
>     rcuop/5-58      [007] d..1. 21951.912853: rcu_batch_start: rcu_preempt
> CBs=193 bl=10
>     rcuop/5-58      [007] ..... 21951.912975: rcu_invoke_callback: rcu_preempt
> rhp=00000000b995fac1 func=wakeme_after_rcu.cfi_jt
> } latency 122 usec
> ...
> <snip>
> 
> now you have a pair.
> 
> --
> Uladzislau Rezki