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authorChristoph Lameter <clameter@sgi.com>2008-02-07 20:47:41 -0500
committerChristoph Lameter <christoph@stapp.engr.sgi.com>2008-02-07 20:47:41 -0500
commit8ff12cfc009a2a38d87fa7058226fe197bb2696f (patch)
tree1358ed247d3c897d8790342a978dd5078354a207 /Documentation/vm/slabinfo.c
parent1f84260c8ce3b1ce26d4c1d6dedc2f33a3a29c0c (diff)
SLUB: Support for performance statistics
The statistics provided here allow the monitoring of allocator behavior but at the cost of some (minimal) loss of performance. Counters are placed in SLUB's per cpu data structure. The per cpu structure may be extended by the statistics to grow larger than one cacheline which will increase the cache footprint of SLUB. There is a compile option to enable/disable the inclusion of the runtime statistics and its off by default. The slabinfo tool is enhanced to support these statistics via two options: -D Switches the line of information displayed for a slab from size mode to activity mode. -A Sorts the slabs displayed by activity. This allows the display of the slabs most important to the performance of a certain load. -r Report option will report detailed statistics on Example (tbench load): slabinfo -AD ->Shows the most active slabs Name Objects Alloc Free %Fast skbuff_fclone_cache 33 111953835 111953835 99 99 :0000192 2666 5283688 5281047 99 99 :0001024 849 5247230 5246389 83 83 vm_area_struct 1349 119642 118355 91 22 :0004096 15 66753 66751 98 98 :0000064 2067 25297 23383 98 78 dentry 10259 28635 18464 91 45 :0000080 11004 18950 8089 98 98 :0000096 1703 12358 10784 99 98 :0000128 762 10582 9875 94 18 :0000512 184 9807 9647 95 81 :0002048 479 9669 9195 83 65 anon_vma 777 9461 9002 99 71 kmalloc-8 6492 9981 5624 99 97 :0000768 258 7174 6931 58 15 So the skbuff_fclone_cache is of highest importance for the tbench load. Pretty high load on the 192 sized slab. Look for the aliases slabinfo -a | grep 000192 :0000192 <- xfs_btree_cur filp kmalloc-192 uid_cache tw_sock_TCP request_sock_TCPv6 tw_sock_TCPv6 skbuff_head_cache xfs_ili Likely skbuff_head_cache. Looking into the statistics of the skbuff_fclone_cache is possible through slabinfo skbuff_fclone_cache ->-r option implied if cache name is mentioned .... Usual output ... Slab Perf Counter Alloc Free %Al %Fr -------------------------------------------------- Fastpath 111953360 111946981 99 99 Slowpath 1044 7423 0 0 Page Alloc 272 264 0 0 Add partial 25 325 0 0 Remove partial 86 264 0 0 RemoteObj/SlabFrozen 350 4832 0 0 Total 111954404 111954404 Flushes 49 Refill 0 Deactivate Full=325(92%) Empty=0(0%) ToHead=24(6%) ToTail=1(0%) Looks good because the fastpath is overwhelmingly taken. skbuff_head_cache: Slab Perf Counter Alloc Free %Al %Fr -------------------------------------------------- Fastpath 5297262 5259882 99 99 Slowpath 4477 39586 0 0 Page Alloc 937 824 0 0 Add partial 0 2515 0 0 Remove partial 1691 824 0 0 RemoteObj/SlabFrozen 2621 9684 0 0 Total 5301739 5299468 Deactivate Full=2620(100%) Empty=0(0%) ToHead=0(0%) ToTail=0(0%) Descriptions of the output: Total: The total number of allocation and frees that occurred for a slab Fastpath: The number of allocations/frees that used the fastpath. Slowpath: Other allocations Page Alloc: Number of calls to the page allocator as a result of slowpath processing Add Partial: Number of slabs added to the partial list through free or alloc (occurs during cpuslab flushes) Remove Partial: Number of slabs removed from the partial list as a result of allocations retrieving a partial slab or by a free freeing the last object of a slab. RemoteObj/Froz: How many times were remotely freed object encountered when a slab was about to be deactivated. Frozen: How many times was free able to skip list processing because the slab was in use as the cpuslab of another processor. Flushes: Number of times the cpuslab was flushed on request (kmem_cache_shrink, may result from races in __slab_alloc) Refill: Number of times we were able to refill the cpuslab from remotely freed objects for the same slab. Deactivate: Statistics how slabs were deactivated. Shows how they were put onto the partial list. In general fastpath is very good. Slowpath without partial list processing is also desirable. Any touching of partial list uses node specific locks which may potentially cause list lock contention. Signed-off-by: Christoph Lameter <clameter@sgi.com>
Diffstat (limited to 'Documentation/vm/slabinfo.c')
-rw-r--r--Documentation/vm/slabinfo.c149
1 files changed, 138 insertions, 11 deletions
diff --git a/Documentation/vm/slabinfo.c b/Documentation/vm/slabinfo.c
index 488c1f31b992..7123fee708ca 100644
--- a/Documentation/vm/slabinfo.c
+++ b/Documentation/vm/slabinfo.c
@@ -32,6 +32,13 @@ struct slabinfo {
32 int sanity_checks, slab_size, store_user, trace; 32 int sanity_checks, slab_size, store_user, trace;
33 int order, poison, reclaim_account, red_zone; 33 int order, poison, reclaim_account, red_zone;
34 unsigned long partial, objects, slabs; 34 unsigned long partial, objects, slabs;
35 unsigned long alloc_fastpath, alloc_slowpath;
36 unsigned long free_fastpath, free_slowpath;
37 unsigned long free_frozen, free_add_partial, free_remove_partial;
38 unsigned long alloc_from_partial, alloc_slab, free_slab, alloc_refill;
39 unsigned long cpuslab_flush, deactivate_full, deactivate_empty;
40 unsigned long deactivate_to_head, deactivate_to_tail;
41 unsigned long deactivate_remote_frees;
35 int numa[MAX_NODES]; 42 int numa[MAX_NODES];
36 int numa_partial[MAX_NODES]; 43 int numa_partial[MAX_NODES];
37} slabinfo[MAX_SLABS]; 44} slabinfo[MAX_SLABS];
@@ -64,8 +71,10 @@ int show_inverted = 0;
64int show_single_ref = 0; 71int show_single_ref = 0;
65int show_totals = 0; 72int show_totals = 0;
66int sort_size = 0; 73int sort_size = 0;
74int sort_active = 0;
67int set_debug = 0; 75int set_debug = 0;
68int show_ops = 0; 76int show_ops = 0;
77int show_activity = 0;
69 78
70/* Debug options */ 79/* Debug options */
71int sanity = 0; 80int sanity = 0;
@@ -93,8 +102,10 @@ void usage(void)
93 printf("slabinfo 5/7/2007. (c) 2007 sgi. clameter@sgi.com\n\n" 102 printf("slabinfo 5/7/2007. (c) 2007 sgi. clameter@sgi.com\n\n"
94 "slabinfo [-ahnpvtsz] [-d debugopts] [slab-regexp]\n" 103 "slabinfo [-ahnpvtsz] [-d debugopts] [slab-regexp]\n"
95 "-a|--aliases Show aliases\n" 104 "-a|--aliases Show aliases\n"
105 "-A|--activity Most active slabs first\n"
96 "-d<options>|--debug=<options> Set/Clear Debug options\n" 106 "-d<options>|--debug=<options> Set/Clear Debug options\n"
97 "-e|--empty Show empty slabs\n" 107 "-D|--display-active Switch line format to activity\n"
108 "-e|--empty Show empty slabs\n"
98 "-f|--first-alias Show first alias\n" 109 "-f|--first-alias Show first alias\n"
99 "-h|--help Show usage information\n" 110 "-h|--help Show usage information\n"
100 "-i|--inverted Inverted list\n" 111 "-i|--inverted Inverted list\n"
@@ -281,8 +292,11 @@ int line = 0;
281 292
282void first_line(void) 293void first_line(void)
283{ 294{
284 printf("Name Objects Objsize Space " 295 if (show_activity)
285 "Slabs/Part/Cpu O/S O %%Fr %%Ef Flg\n"); 296 printf("Name Objects Alloc Free %%Fast\n");
297 else
298 printf("Name Objects Objsize Space "
299 "Slabs/Part/Cpu O/S O %%Fr %%Ef Flg\n");
286} 300}
287 301
288/* 302/*
@@ -309,6 +323,12 @@ unsigned long slab_size(struct slabinfo *s)
309 return s->slabs * (page_size << s->order); 323 return s->slabs * (page_size << s->order);
310} 324}
311 325
326unsigned long slab_activity(struct slabinfo *s)
327{
328 return s->alloc_fastpath + s->free_fastpath +
329 s->alloc_slowpath + s->free_slowpath;
330}
331
312void slab_numa(struct slabinfo *s, int mode) 332void slab_numa(struct slabinfo *s, int mode)
313{ 333{
314 int node; 334 int node;
@@ -392,6 +412,71 @@ const char *onoff(int x)
392 return "Off"; 412 return "Off";
393} 413}
394 414
415void slab_stats(struct slabinfo *s)
416{
417 unsigned long total_alloc;
418 unsigned long total_free;
419 unsigned long total;
420
421 if (!s->alloc_slab)
422 return;
423
424 total_alloc = s->alloc_fastpath + s->alloc_slowpath;
425 total_free = s->free_fastpath + s->free_slowpath;
426
427 if (!total_alloc)
428 return;
429
430 printf("\n");
431 printf("Slab Perf Counter Alloc Free %%Al %%Fr\n");
432 printf("--------------------------------------------------\n");
433 printf("Fastpath %8lu %8lu %3lu %3lu\n",
434 s->alloc_fastpath, s->free_fastpath,
435 s->alloc_fastpath * 100 / total_alloc,
436 s->free_fastpath * 100 / total_free);
437 printf("Slowpath %8lu %8lu %3lu %3lu\n",
438 total_alloc - s->alloc_fastpath, s->free_slowpath,
439 (total_alloc - s->alloc_fastpath) * 100 / total_alloc,
440 s->free_slowpath * 100 / total_free);
441 printf("Page Alloc %8lu %8lu %3lu %3lu\n",
442 s->alloc_slab, s->free_slab,
443 s->alloc_slab * 100 / total_alloc,
444 s->free_slab * 100 / total_free);
445 printf("Add partial %8lu %8lu %3lu %3lu\n",
446 s->deactivate_to_head + s->deactivate_to_tail,
447 s->free_add_partial,
448 (s->deactivate_to_head + s->deactivate_to_tail) * 100 / total_alloc,
449 s->free_add_partial * 100 / total_free);
450 printf("Remove partial %8lu %8lu %3lu %3lu\n",
451 s->alloc_from_partial, s->free_remove_partial,
452 s->alloc_from_partial * 100 / total_alloc,
453 s->free_remove_partial * 100 / total_free);
454
455 printf("RemoteObj/SlabFrozen %8lu %8lu %3lu %3lu\n",
456 s->deactivate_remote_frees, s->free_frozen,
457 s->deactivate_remote_frees * 100 / total_alloc,
458 s->free_frozen * 100 / total_free);
459
460 printf("Total %8lu %8lu\n\n", total_alloc, total_free);
461
462 if (s->cpuslab_flush)
463 printf("Flushes %8lu\n", s->cpuslab_flush);
464
465 if (s->alloc_refill)
466 printf("Refill %8lu\n", s->alloc_refill);
467
468 total = s->deactivate_full + s->deactivate_empty +
469 s->deactivate_to_head + s->deactivate_to_tail;
470
471 if (total)
472 printf("Deactivate Full=%lu(%lu%%) Empty=%lu(%lu%%) "
473 "ToHead=%lu(%lu%%) ToTail=%lu(%lu%%)\n",
474 s->deactivate_full, (s->deactivate_full * 100) / total,
475 s->deactivate_empty, (s->deactivate_empty * 100) / total,
476 s->deactivate_to_head, (s->deactivate_to_head * 100) / total,
477 s->deactivate_to_tail, (s->deactivate_to_tail * 100) / total);
478}
479
395void report(struct slabinfo *s) 480void report(struct slabinfo *s)
396{ 481{
397 if (strcmp(s->name, "*") == 0) 482 if (strcmp(s->name, "*") == 0)
@@ -430,6 +515,7 @@ void report(struct slabinfo *s)
430 ops(s); 515 ops(s);
431 show_tracking(s); 516 show_tracking(s);
432 slab_numa(s, 1); 517 slab_numa(s, 1);
518 slab_stats(s);
433} 519}
434 520
435void slabcache(struct slabinfo *s) 521void slabcache(struct slabinfo *s)
@@ -479,13 +565,27 @@ void slabcache(struct slabinfo *s)
479 *p++ = 'T'; 565 *p++ = 'T';
480 566
481 *p = 0; 567 *p = 0;
482 printf("%-21s %8ld %7d %8s %14s %4d %1d %3ld %3ld %s\n", 568 if (show_activity) {
483 s->name, s->objects, s->object_size, size_str, dist_str, 569 unsigned long total_alloc;
484 s->objs_per_slab, s->order, 570 unsigned long total_free;
485 s->slabs ? (s->partial * 100) / s->slabs : 100, 571
486 s->slabs ? (s->objects * s->object_size * 100) / 572 total_alloc = s->alloc_fastpath + s->alloc_slowpath;
487 (s->slabs * (page_size << s->order)) : 100, 573 total_free = s->free_fastpath + s->free_slowpath;
488 flags); 574
575 printf("%-21s %8ld %8ld %8ld %3ld %3ld \n",
576 s->name, s->objects,
577 total_alloc, total_free,
578 total_alloc ? (s->alloc_fastpath * 100 / total_alloc) : 0,
579 total_free ? (s->free_fastpath * 100 / total_free) : 0);
580 }
581 else
582 printf("%-21s %8ld %7d %8s %14s %4d %1d %3ld %3ld %s\n",
583 s->name, s->objects, s->object_size, size_str, dist_str,
584 s->objs_per_slab, s->order,
585 s->slabs ? (s->partial * 100) / s->slabs : 100,
586 s->slabs ? (s->objects * s->object_size * 100) /
587 (s->slabs * (page_size << s->order)) : 100,
588 flags);
489} 589}
490 590
491/* 591/*
@@ -892,6 +992,8 @@ void sort_slabs(void)
892 992
893 if (sort_size) 993 if (sort_size)
894 result = slab_size(s1) < slab_size(s2); 994 result = slab_size(s1) < slab_size(s2);
995 else if (sort_active)
996 result = slab_activity(s1) < slab_activity(s2);
895 else 997 else
896 result = strcasecmp(s1->name, s2->name); 998 result = strcasecmp(s1->name, s2->name);
897 999
@@ -1074,6 +1176,23 @@ void read_slab_dir(void)
1074 free(t); 1176 free(t);
1075 slab->store_user = get_obj("store_user"); 1177 slab->store_user = get_obj("store_user");
1076 slab->trace = get_obj("trace"); 1178 slab->trace = get_obj("trace");
1179 slab->alloc_fastpath = get_obj("alloc_fastpath");
1180 slab->alloc_slowpath = get_obj("alloc_slowpath");
1181 slab->free_fastpath = get_obj("free_fastpath");
1182 slab->free_slowpath = get_obj("free_slowpath");
1183 slab->free_frozen= get_obj("free_frozen");
1184 slab->free_add_partial = get_obj("free_add_partial");
1185 slab->free_remove_partial = get_obj("free_remove_partial");
1186 slab->alloc_from_partial = get_obj("alloc_from_partial");
1187 slab->alloc_slab = get_obj("alloc_slab");
1188 slab->alloc_refill = get_obj("alloc_refill");
1189 slab->free_slab = get_obj("free_slab");
1190 slab->cpuslab_flush = get_obj("cpuslab_flush");
1191 slab->deactivate_full = get_obj("deactivate_full");
1192 slab->deactivate_empty = get_obj("deactivate_empty");
1193 slab->deactivate_to_head = get_obj("deactivate_to_head");
1194 slab->deactivate_to_tail = get_obj("deactivate_to_tail");
1195 slab->deactivate_remote_frees = get_obj("deactivate_remote_frees");
1077 chdir(".."); 1196 chdir("..");
1078 if (slab->name[0] == ':') 1197 if (slab->name[0] == ':')
1079 alias_targets++; 1198 alias_targets++;
@@ -1124,7 +1243,9 @@ void output_slabs(void)
1124 1243
1125struct option opts[] = { 1244struct option opts[] = {
1126 { "aliases", 0, NULL, 'a' }, 1245 { "aliases", 0, NULL, 'a' },
1246 { "activity", 0, NULL, 'A' },
1127 { "debug", 2, NULL, 'd' }, 1247 { "debug", 2, NULL, 'd' },
1248 { "display-activity", 0, NULL, 'D' },
1128 { "empty", 0, NULL, 'e' }, 1249 { "empty", 0, NULL, 'e' },
1129 { "first-alias", 0, NULL, 'f' }, 1250 { "first-alias", 0, NULL, 'f' },
1130 { "help", 0, NULL, 'h' }, 1251 { "help", 0, NULL, 'h' },
@@ -1149,7 +1270,7 @@ int main(int argc, char *argv[])
1149 1270
1150 page_size = getpagesize(); 1271 page_size = getpagesize();
1151 1272
1152 while ((c = getopt_long(argc, argv, "ad::efhil1noprstvzTS", 1273 while ((c = getopt_long(argc, argv, "aAd::Defhil1noprstvzTS",
1153 opts, NULL)) != -1) 1274 opts, NULL)) != -1)
1154 switch (c) { 1275 switch (c) {
1155 case '1': 1276 case '1':
@@ -1158,11 +1279,17 @@ int main(int argc, char *argv[])
1158 case 'a': 1279 case 'a':
1159 show_alias = 1; 1280 show_alias = 1;
1160 break; 1281 break;
1282 case 'A':
1283 sort_active = 1;
1284 break;
1161 case 'd': 1285 case 'd':
1162 set_debug = 1; 1286 set_debug = 1;
1163 if (!debug_opt_scan(optarg)) 1287 if (!debug_opt_scan(optarg))
1164 fatal("Invalid debug option '%s'\n", optarg); 1288 fatal("Invalid debug option '%s'\n", optarg);
1165 break; 1289 break;
1290 case 'D':
1291 show_activity = 1;
1292 break;
1166 case 'e': 1293 case 'e':
1167 show_empty = 1; 1294 show_empty = 1;
1168 break; 1295 break;