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Add more operation analysis, combine with deletes and inserts variables.
And Using the preprocessor to decide the analysis being set or not. The following are the new varialbes to record the opreations: rtry is the number of retries in the __list_find function. cons is the number of wait-free contains in the __list_find function that curr pointer pointed. trav is the number of list element traversal in the __list_find function. fail is the number of CAS() failures. del is the number of list_delete operation failed and restart again. ins is the number of list_insert operation failed and restart again. load is the number of atomic_load operation in list_delete, list_insert and __list_find. store is the number of atomic_store operation in list_delete, list_insert and __list_find.
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-22
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2 files changed

+166
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‎hp_list/Makefile

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,11 @@
11
all:
22
$(CC) -Wall -o list main.c -lpthread -g -fsanitize=thread
33

4+
# The RUNTIME_STAT allow to show the runtime operation state,
5+
# such as "rtry" is the number of retries in the __list_find function.
6+
analysis:
7+
$(CC) -Wall -D RUNTIME_STAT -o list main.c -lpthread -g -fsanitize=thread
8+
49
indent:
510
clang-format -i *.[ch]
611

‎hp_list/main.c

Lines changed: 161 additions & 22 deletions
Original file line numberDiff line numberDiff line change
@@ -14,6 +14,140 @@
1414
#include <string.h>
1515
#include <threads.h>
1616

17+
#ifdef RUNTIME_STAT
18+
/*
19+
* "rtry" the number of retries in the __list_find function.
20+
* "cons" the number of wait-free contains in the __list_find function that curr
21+
* pointer pointed.
22+
* "trav" the number of list element traversal in the __list_find function.
23+
* "fail" the number of CAS() failures.
24+
* "del" the number of list_delete operation failed and restart again.
25+
* "ins" the number of list_insert operation failed and restart again.
26+
* "load" is the number of atomic_load operation in list_delete, list_insert
27+
* and __list_find.
28+
* "store" is the number of atomic_store operation in list_delete, list_insert
29+
* and __list_find.
30+
*/
31+
static atomic_uint_fast64_t rtry = 0, cons = 0, trav = 0, fail = 0;
32+
static atomic_uint_fast64_t del = 0, ins = 0;
33+
static atomic_uint_fast64_t load = 0, store = 0;
34+
static atomic_uint_fast64_t deletes = 0, inserts = 0;
35+
36+
#define TRACE_GOTO_TRY_AGAIN \
37+
do { \
38+
atomic_fetch_add(&rtry, 1); \
39+
goto try_again; \
40+
} while (0)
41+
#define TRACE_WAIT_FREE_CONS \
42+
do { \
43+
atomic_fetch_add(&cons, 1); \
44+
} while (0)
45+
#define TRACE_TRAVERSAL \
46+
do { \
47+
atomic_fetch_add(&trav, 1); \
48+
} while (0)
49+
#define TRACE_DEL \
50+
do { \
51+
atomic_fetch_add(&del, 1); \
52+
} while (0)
53+
#define TRACE_INS \
54+
do { \
55+
atomic_fetch_add(&ins, 1); \
56+
} while (0)
57+
#define TRACE_DELETES \
58+
do { \
59+
atomic_fetch_add(&deletes, 1); \
60+
} while (0)
61+
#define TRACE_INSERTS \
62+
do { \
63+
atomic_fetch_add(&inserts, 1); \
64+
} while (0)
65+
#define CAS(obj, expected, desired) \
66+
({ \
67+
bool __ret = atomic_compare_exchange_strong(obj, expected, desired); \
68+
if (!__ret) \
69+
atomic_fetch_add(&fail, 1); \
70+
__ret; \
71+
})
72+
#define ATOMIC_LOAD(obj) \
73+
({ \
74+
atomic_fetch_add(&load, 1); \
75+
atomic_load(obj); \
76+
})
77+
#define ATOMIC_STORE_EXPLICIT(obj, desired, order) \
78+
do { \
79+
atomic_fetch_add(&store, 1); \
80+
atomic_store_explicit(obj, desired, order); \
81+
} while (0)
82+
83+
void do_analysis(void)
84+
{
85+
printf(
86+
"\"rtry\" is the number of retries in the __list_find function.\n");
87+
printf(
88+
"\"cons\" is the number of wait-free contains in the __list_find "
89+
"function that curr pointer pointed.\n");
90+
printf(
91+
"\"trav\" is the number of list element traversal in the "
92+
"__list_find function.\n");
93+
printf("\"fail\" is the number of CAS() failures.\n");
94+
printf(
95+
"\"del\" is the number of list_delete operation failed and "
96+
"restart again.\n");
97+
printf(
98+
"\"ins\" is the number of list_insert operation failed and "
99+
"restart again.\n");
100+
printf("\"deletes\" is the number of linked list elements deleted.\n");
101+
printf("\"inserts\" is the number of linked list elements created.\n");
102+
printf(
103+
"\"load\" is the number of atomic_load operation in list_delete, "
104+
"list_insert and __list_find.\n");
105+
printf(
106+
"\"store\" is the number of atomic_store operation in list_delete, "
107+
"list_insert and __list_find.\n");
108+
printf("\n%10s %10s %10s %10s %10s %10s %10s %10s %10s %10s\n", "rtry",
109+
"cons", "trav", "fail", "del", "ins", "load", "store", "deletes",
110+
"inserts");
111+
for (int i = 0; i < 109; i++)
112+
printf("-");
113+
printf("\n%10ld %10ld %10ld %10ld %10ld %10ld %10ld %10ld %10ld %10ld\n",
114+
rtry, cons, trav, fail, del, ins, load, store, deletes, inserts);
115+
}
116+
117+
#else
118+
119+
#define TRACE_GOTO_TRY_AGAIN \
120+
do { \
121+
goto try_again; \
122+
} while (0)
123+
#define TRACE_WAIT_FREE_CONS \
124+
do { \
125+
} while (0)
126+
#define TRACE_TRAVERSAL \
127+
do { \
128+
} while (0)
129+
#define TRACE_DEL \
130+
do { \
131+
} while (0)
132+
#define TRACE_INS \
133+
do { \
134+
} while (0)
135+
#define TRACE_DELETES \
136+
do { \
137+
} while (0)
138+
#define TRACE_INSERTS \
139+
do { \
140+
} while (0)
141+
#define CAS(obj, expected, desired) \
142+
({ atomic_compare_exchange_strong(obj, expected, desired); })
143+
#define ATOMIC_LOAD(obj) ({ atomic_load(obj); })
144+
#define ATOMIC_STORE_EXPLICIT(obj, desired, order) \
145+
do { \
146+
atomic_store_explicit(obj, desired, order); \
147+
} while (0)
148+
149+
#endif
150+
17151
#define HP_MAX_THREADS 128
18152
#define HP_MAX_HPS 5 /* This is named 'K' in the HP paper */
19153
#define CLPAD (128 / sizeof(uintptr_t))
@@ -162,8 +296,6 @@ void list_hp_retire(list_hp_t *hp, uintptr_t ptr)
162296
#define N_THREADS (128 / 2)
163297
#define MAX_THREADS 128
164298

165-
static atomic_uint_fast32_t deletes = 0, inserts = 0;
166-
167299
enum { HP_NEXT = 0, HP_CURR = 1, HP_PREV };
168300

169301
#define is_marked(p) (bool) ((uintptr_t)(p) &0x01)
@@ -195,7 +327,7 @@ list_node_t *list_node_new(list_key_t key)
195327
list_node_t *node = aligned_alloc(128, sizeof(*node));
196328
assert(node);
197329
*node = (list_node_t){.magic = LIST_MAGIC, .key = key};
198-
(void) atomic_fetch_add(&inserts, 1);
330+
TRACE_INSERTS;
199331
return node;
200332
}
201333

@@ -205,7 +337,7 @@ void list_node_destroy(list_node_t *node)
205337
return;
206338
assert(node->magic == LIST_MAGIC);
207339
free(node);
208-
(void) atomic_fetch_add(&deletes, 1);
340+
TRACE_DELETES;
209341
}
210342

211343
static void __list_node_delete(void *arg)
@@ -225,21 +357,25 @@ static bool __list_find(list_t *list,
225357

226358
try_again:
227359
prev = &list->head;
228-
curr = (list_node_t *) atomic_load(prev);
360+
curr = (list_node_t *) ATOMIC_LOAD(prev);
229361
(void) list_hp_protect_ptr(list->hp, HP_CURR, (uintptr_t) curr);
230-
if (atomic_load(prev) != get_unmarked(curr))
231-
goto try_again;
362+
if (ATOMIC_LOAD(prev) != get_unmarked(curr))
363+
TRACE_GOTO_TRY_AGAIN;
232364
while (true) {
233-
next = (list_node_t *) atomic_load(&get_unmarked_node(curr)->next);
365+
#ifdef RUNTIME_STAT
366+
if (is_marked(curr))
367+
TRACE_WAIT_FREE_CONS;
368+
#endif
369+
next = (list_node_t *) ATOMIC_LOAD(&get_unmarked_node(curr)->next);
234370
(void) list_hp_protect_ptr(list->hp, HP_NEXT, get_unmarked(next));
235371
/* On a CAS failure, the search function, "__list_find," will simply
236372
* have to go backwards in the list until an unmarked element is found
237373
* from which the search in increasing key order can be started.
238374
*/
239-
if (atomic_load(&get_unmarked_node(curr)->next) != (uintptr_t) next)
240-
goto try_again;
241-
if (atomic_load(prev) != get_unmarked(curr))
242-
goto try_again;
375+
if (ATOMIC_LOAD(&get_unmarked_node(curr)->next) != (uintptr_t) next)
376+
TRACE_GOTO_TRY_AGAIN;
377+
if (ATOMIC_LOAD(prev) != get_unmarked(curr))
378+
TRACE_GOTO_TRY_AGAIN;
243379
if (get_unmarked_node(next) == next) {
244380
if (!(get_unmarked_node(curr)->key < *key)) {
245381
*par_curr = curr;
@@ -252,12 +388,13 @@ static bool __list_find(list_t *list,
252388
get_unmarked(curr));
253389
} else {
254390
uintptr_t tmp = get_unmarked(curr);
255-
if (!atomic_compare_exchange_strong(prev, &tmp, get_unmarked(next)))
256-
goto try_again;
391+
if (!CAS(prev, &tmp, get_unmarked(next)))
392+
TRACE_GOTO_TRY_AGAIN;
257393
list_hp_retire(list->hp, get_unmarked(curr));
258394
}
259395
curr = next;
260396
(void) list_hp_protect_release(list->hp, HP_CURR, get_unmarked(next));
397+
TRACE_TRAVERSAL;
261398
}
262399
}
263400

@@ -274,13 +411,14 @@ bool list_insert(list_t *list, list_key_t key)
274411
list_hp_clear(list->hp);
275412
return false;
276413
}
277-
atomic_store_explicit(&node->next, (uintptr_t) curr,
414+
ATOMIC_STORE_EXPLICIT(&node->next, (uintptr_t) curr,
278415
memory_order_relaxed);
279416
uintptr_t tmp = get_unmarked(curr);
280-
if (atomic_compare_exchange_strong(prev, &tmp, (uintptr_t) node)) {
417+
if (CAS(prev, &tmp, (uintptr_t) node)) {
281418
list_hp_clear(list->hp);
282419
return true;
283420
}
421+
TRACE_INS;
284422
}
285423
}
286424

@@ -296,12 +434,13 @@ bool list_delete(list_t *list, list_key_t key)
296434

297435
uintptr_t tmp = get_unmarked(next);
298436

299-
if (!atomic_compare_exchange_strong(&curr->next, &tmp,
300-
get_marked(next)))
437+
if (!CAS(&curr->next, &tmp, get_marked(next))) {
438+
TRACE_DEL;
301439
continue;
440+
}
302441

303442
tmp = get_unmarked(curr);
304-
if (atomic_compare_exchange_strong(prev, &tmp, get_unmarked(next))) {
443+
if (CAS(prev, &tmp, get_unmarked(next))) {
305444
list_hp_clear(list->hp);
306445
list_hp_retire(list->hp, get_unmarked(curr));
307446
} else {
@@ -382,8 +521,8 @@ int main(void)
382521

383522
list_destroy(list);
384523

385-
fprintf(stderr, "inserts = %zu, deletes = %zu\n", atomic_load(&inserts),
386-
atomic_load(&deletes));
387-
524+
#ifdef RUNTIME_STAT
525+
do_analysis();
526+
#endif
388527
return 0;
389528
}

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