From: Mathieu Desnoyers Date: Sun, 23 Jun 2013 17:40:42 +0000 (-0400) Subject: doc/examples: cds_lfht_add/cds_lfht_del X-Git-Tag: v0.8.0~18 X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=f7e7a1b86b06da9d2cef60e43039fa8c8ae6479a;p=urcu.git doc/examples: cds_lfht_add/cds_lfht_del Signed-off-by: Mathieu Desnoyers --- diff --git a/.gitignore b/.gitignore index 47046ed..9f46a43 100644 --- a/.gitignore +++ b/.gitignore @@ -106,6 +106,9 @@ doc/examples/lfstack/cds_lfs_push doc/examples/lfstack/cds_lfs_pop_blocking doc/examples/lfstack/cds_lfs_pop_all_blocking +doc/examples/rculfhash/cds_lfht_add +doc/examples/rculfhash/cds_lfht_del + #automake /config.h .deps/ diff --git a/doc/examples/Makefile.am b/doc/examples/Makefile.am index 40c211a..75021aa 100644 --- a/doc/examples/Makefile.am +++ b/doc/examples/Makefile.am @@ -91,6 +91,16 @@ dist_doc_examples_rculfqueue_DATA = \ rculfqueue/cds_lfq_enqueue.c \ rculfqueue/cds_lfq_dequeue.c +doc_examples_rculfhashdir = ${doc_examplesdir}/rculfhash + +dist_doc_examples_rculfhash_DATA = \ + rculfhash/Makefile \ + rculfhash/jhash.h \ + rculfhash/Makefile.cds_lfht_add \ + rculfhash/Makefile.cds_lfht_del \ + rculfhash/cds_lfht_add.c \ + rculfhash/cds_lfht_del.c + if NO_SHARED # Don't build examples if shared libraries support was explicitly # disabled. diff --git a/doc/examples/Makefile.examples.template b/doc/examples/Makefile.examples.template index 4d26cb0..badecff 100644 --- a/doc/examples/Makefile.examples.template +++ b/doc/examples/Makefile.examples.template @@ -20,7 +20,7 @@ $(BINARY): $(OBJECTS) $(CC) $(CFLAGS) $(LDFLAGS) $(AM_CFLAGS) $(AM_LDFLAGS) \ $(LIBS) -o $@ $(OBJECTS) -$(OBJECTS): $(SOURCES) +$(OBJECTS): $(SOURCES) $(DEPS) $(CC) $(CPPFLAGS) $(CFLAGS) $(AM_CPPFLAGS) $(AM_CFLAGS) \ -c -o $@ $(SOURCES) diff --git a/doc/examples/dist-files/Makefile b/doc/examples/dist-files/Makefile index 4006613..cb380b7 100644 --- a/doc/examples/dist-files/Makefile +++ b/doc/examples/dist-files/Makefile @@ -19,6 +19,7 @@ all: $(MAKE) -C rculfqueue $(MAKE) -C wfstack $(MAKE) -C lfstack + $(MAKE) -C rculfhash .PHONY: clean clean: @@ -29,3 +30,4 @@ clean: $(MAKE) -C rculfqueue clean $(MAKE) -C wfstack clean $(MAKE) -C lfstack clean + $(MAKE) -C rculfhash clean diff --git a/doc/examples/rculfhash/Makefile b/doc/examples/rculfhash/Makefile new file mode 100644 index 0000000..87a6faf --- /dev/null +++ b/doc/examples/rculfhash/Makefile @@ -0,0 +1,20 @@ +# Copyright (C) 2013 Mathieu Desnoyers +# +# THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED +# OR IMPLIED. ANY USE IS AT YOUR OWN RISK. +# +# Permission is hereby granted to use or copy this program for any +# purpose, provided the above notices are retained on all copies. +# Permission to modify the code and to distribute modified code is +# granted, provided the above notices are retained, and a notice that +# the code was modified is included with the above copyright notice. +# +# This makefile is purposefully kept simple to support GNU and BSD make. + +all: + $(MAKE) -f Makefile.cds_lfht_add + $(MAKE) -f Makefile.cds_lfht_del + +.PHONY: clean +clean: + $(MAKE) -f Makefile.cds_lfht_del clean diff --git a/doc/examples/rculfhash/Makefile.cds_lfht_add b/doc/examples/rculfhash/Makefile.cds_lfht_add new file mode 100644 index 0000000..9fab2b6 --- /dev/null +++ b/doc/examples/rculfhash/Makefile.cds_lfht_add @@ -0,0 +1,22 @@ +# Copyright (C) 2013 Mathieu Desnoyers +# +# THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED +# OR IMPLIED. ANY USE IS AT YOUR OWN RISK. +# +# Permission is hereby granted to use or copy this program for any +# purpose, provided the above notices are retained on all copies. +# Permission to modify the code and to distribute modified code is +# granted, provided the above notices are retained, and a notice that +# the code was modified is included with the above copyright notice. +# +# This makefile is purposefully kept simple to support GNU and BSD make. + +EXAMPLE_NAME = cds_lfht_add + +SOURCES = $(EXAMPLE_NAME).c +DEPS = jhash.h +OBJECTS = $(EXAMPLE_NAME).o +BINARY = $(EXAMPLE_NAME) +LIBS = -lurcu-cds -lurcu + +include ../Makefile.examples.template diff --git a/doc/examples/rculfhash/Makefile.cds_lfht_del b/doc/examples/rculfhash/Makefile.cds_lfht_del new file mode 100644 index 0000000..6377490 --- /dev/null +++ b/doc/examples/rculfhash/Makefile.cds_lfht_del @@ -0,0 +1,22 @@ +# Copyright (C) 2013 Mathieu Desnoyers +# +# THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED +# OR IMPLIED. ANY USE IS AT YOUR OWN RISK. +# +# Permission is hereby granted to use or copy this program for any +# purpose, provided the above notices are retained on all copies. +# Permission to modify the code and to distribute modified code is +# granted, provided the above notices are retained, and a notice that +# the code was modified is included with the above copyright notice. +# +# This makefile is purposefully kept simple to support GNU and BSD make. + +EXAMPLE_NAME = cds_lfht_del + +SOURCES = $(EXAMPLE_NAME).c +DEPS = jhash.h +OBJECTS = $(EXAMPLE_NAME).o +BINARY = $(EXAMPLE_NAME) +LIBS = -lurcu-cds -lurcu + +include ../Makefile.examples.template diff --git a/doc/examples/rculfhash/cds_lfht_add.c b/doc/examples/rculfhash/cds_lfht_add.c new file mode 100644 index 0000000..8932e7a --- /dev/null +++ b/doc/examples/rculfhash/cds_lfht_add.c @@ -0,0 +1,106 @@ +/* + * Copyright (C) 2013 Mathieu Desnoyers + * + * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED + * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. + * + * Permission is hereby granted to use or copy this program for any + * purpose, provided the above notices are retained on all copies. + * Permission to modify the code and to distribute modified code is + * granted, provided the above notices are retained, and a notice that + * the code was modified is included with the above copyright notice. + * + * This example shows how to add nodes (allowing duplicate keys) into a + * RCU lock-free hash table. + * This hash table requires using a RCU scheme. + */ + +#include +#include +#include + +#include /* RCU flavor */ +#include /* RCU Lock-free hash table */ +#include /* For CAA_ARRAY_SIZE */ +#include "jhash.h" /* Example hash function */ + +/* + * Nodes populated into the hash table. + */ +struct mynode { + int value; /* Node content */ + struct cds_lfht_node node; /* Chaining in hash table */ +}; + +int main(int argc, char **argv) +{ + int values[] = { -5, 42, 42, 36, 24, }; /* 42 is duplicated */ + struct cds_lfht *ht; /* Hash table */ + unsigned int i; + int ret = 0; + uint32_t seed; + struct cds_lfht_iter iter; /* For iteration on hash table */ + struct mynode *node; + + /* + * Each thread need using RCU read-side need to be explicitly + * registered. + */ + rcu_register_thread(); + + /* Use time as seed for hash table hashing. */ + seed = (uint32_t) time(NULL); + + /* + * Allocate hash table. + */ + ht = cds_lfht_new(1, 1, 0, + CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, + NULL); + if (!ht) { + printf("Error allocating hash table\n"); + ret = -1; + goto end; + } + + /* + * Add nodes to hash table. + */ + for (i = 0; i < CAA_ARRAY_SIZE(values); i++) { + unsigned long hash; + + node = malloc(sizeof(*node)); + if (!node) { + ret = -1; + goto end; + } + + cds_lfht_node_init(&node->node); + node->value = values[i]; + hash = jhash(&values[i], sizeof(values[i]), seed); + + /* + * cds_lfht_add() needs to be called from RCU read-side + * critical section. + */ + rcu_read_lock(); + cds_lfht_add(ht, hash, &node->node); + rcu_read_unlock(); + } + + /* + * Iterate over each hash table node. Those will appear in + * random order, depending on the hash seed. Iteration needs to + * be performed within RCU read-side critical section. + */ + printf("hash table content (random order):"); + rcu_read_lock(); + cds_lfht_for_each_entry(ht, &iter, node, node) { + printf(" %d", node->value); + } + rcu_read_unlock(); + printf("\n"); +end: + rcu_unregister_thread(); + return ret; +} diff --git a/doc/examples/rculfhash/cds_lfht_del.c b/doc/examples/rculfhash/cds_lfht_del.c new file mode 100644 index 0000000..d5a7264 --- /dev/null +++ b/doc/examples/rculfhash/cds_lfht_del.c @@ -0,0 +1,154 @@ +/* + * Copyright (C) 2013 Mathieu Desnoyers + * + * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED + * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. + * + * Permission is hereby granted to use or copy this program for any + * purpose, provided the above notices are retained on all copies. + * Permission to modify the code and to distribute modified code is + * granted, provided the above notices are retained, and a notice that + * the code was modified is included with the above copyright notice. + * + * This example shows how to remove nodes from a RCU lock-free hash table. + * This hash table requires using a RCU scheme. + */ + +#include +#include +#include + +#include /* RCU flavor */ +#include /* RCU Lock-free hash table */ +#include /* For CAA_ARRAY_SIZE */ +#include "jhash.h" /* Example hash function */ + +/* + * Nodes populated into the hash table. + */ +struct mynode { + int value; /* Node content */ + struct cds_lfht_node node; /* Chaining in hash table */ + struct rcu_head rcu_head; /* For call_rcu() */ +}; + +int match(struct cds_lfht_node *ht_node, const void *_key) +{ + struct mynode *node = + caa_container_of(ht_node, struct mynode, node); + const unsigned int *key = _key; + + return *key == node->value; +} + +int main(int argc, char **argv) +{ + int values[] = { -5, 42, 42, 36, 24, }; /* 42 is duplicated */ + int remove_values[] = { 42, 36, 24, 123, }; + struct cds_lfht *ht; /* Hash table */ + unsigned int i; + int ret = 0; + uint32_t seed; + struct cds_lfht_iter iter; /* For iteration on hash table */ + struct cds_lfht_node *ht_node; + struct mynode *node; + + /* + * Each thread need using RCU read-side need to be explicitly + * registered. + */ + rcu_register_thread(); + + /* Use time as seed for hash table hashing. */ + seed = (uint32_t) time(NULL); + + /* + * Allocate hash table. + */ + ht = cds_lfht_new(1, 1, 0, + CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, + NULL); + if (!ht) { + printf("Error allocating hash table\n"); + ret = -1; + goto end; + } + + /* + * Add nodes to hash table. + */ + for (i = 0; i < CAA_ARRAY_SIZE(values); i++) { + unsigned long hash; + int value; + + node = malloc(sizeof(*node)); + if (!node) { + ret = -1; + goto end; + } + + cds_lfht_node_init(&node->node); + value = values[i]; + node->value = value; + hash = jhash(&value, sizeof(value), seed); + + /* + * cds_lfht_add() needs to be called from RCU read-side + * critical section. + */ + rcu_read_lock(); + cds_lfht_add(ht, hash, &node->node); + rcu_read_unlock(); + } + + /* + * Iterate over each hash table node. Those will appear in + * random order, depending on the hash seed. Iteration needs to + * be performed within RCU read-side critical section. + */ + printf("hash table content (random order):"); + rcu_read_lock(); + cds_lfht_for_each_entry(ht, &iter, node, node) { + printf(" %d", node->value); + } + rcu_read_unlock(); + printf("\n"); + + /* + * Remove one node for each key, if such a node is present. + */ + printf("removing keys (single key, not duplicates):"); + for (i = 0; i < CAA_ARRAY_SIZE(remove_values); i++) { + unsigned long hash; + int value; + + value = remove_values[i]; + hash = jhash(&value, sizeof(value), seed); + printf(" %d", value); + rcu_read_lock(); + cds_lfht_lookup(ht, hash, match, &value, &iter); + ht_node = cds_lfht_iter_get_node(&iter); + if (ht_node) { + ret = cds_lfht_del(ht, ht_node); + if (ret) { + printf(" (concurrently deleted)"); + } + } else { + printf(" (not found)"); + } + rcu_read_unlock(); + } + printf("\n"); + + printf("hash table content (random order):"); + rcu_read_lock(); + cds_lfht_for_each_entry(ht, &iter, node, node) { + printf(" %d", node->value); + } + rcu_read_unlock(); + printf("\n"); + +end: + rcu_unregister_thread(); + return ret; +} diff --git a/doc/examples/rculfhash/jhash.h b/doc/examples/rculfhash/jhash.h new file mode 100644 index 0000000..673989d --- /dev/null +++ b/doc/examples/rculfhash/jhash.h @@ -0,0 +1,256 @@ +#ifndef _JHASH_H +#define _JHASH_H + +/* + * jhash.h + * + * Example hash function. + * + * Copyright 2009-2012 - Mathieu Desnoyers + * + * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED + * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. + * + * Permission is hereby granted to use or copy this program for any + * purpose, provided the above notices are retained on all copies. + * Permission to modify the code and to distribute modified code is + * granted, provided the above notices are retained, and a notice that + * the code was modified is included with the above copyright notice. + */ + +/* + * Hash function + * Source: http://burtleburtle.net/bob/c/lookup3.c + * Originally Public Domain + */ + +#define rot(x, k) (((x) << (k)) | ((x) >> (32 - (k)))) + +#define mix(a, b, c) \ +do { \ + a -= c; a ^= rot(c, 4); c += b; \ + b -= a; b ^= rot(a, 6); a += c; \ + c -= b; c ^= rot(b, 8); b += a; \ + a -= c; a ^= rot(c, 16); c += b; \ + b -= a; b ^= rot(a, 19); a += c; \ + c -= b; c ^= rot(b, 4); b += a; \ +} while (0) + +#define final(a, b, c) \ +{ \ + c ^= b; c -= rot(b, 14); \ + a ^= c; a -= rot(c, 11); \ + b ^= a; b -= rot(a, 25); \ + c ^= b; c -= rot(b, 16); \ + a ^= c; a -= rot(c, 4); \ + b ^= a; b -= rot(a, 14); \ + c ^= b; c -= rot(b, 24); \ +} + +#if (BYTE_ORDER == LITTLE_ENDIAN) +#define HASH_LITTLE_ENDIAN 1 +#else +#define HASH_LITTLE_ENDIAN 0 +#endif + +/* + * + * hashlittle() -- hash a variable-length key into a 32-bit value + * k : the key (the unaligned variable-length array of bytes) + * length : the length of the key, counting by bytes + * initval : can be any 4-byte value + * Returns a 32-bit value. Every bit of the key affects every bit of + * the return value. Two keys differing by one or two bits will have + * totally different hash values. + * + * The best hash table sizes are powers of 2. There is no need to do + * mod a prime (mod is sooo slow!). If you need less than 32 bits, + * use a bitmask. For example, if you need only 10 bits, do + * h = (h & hashmask(10)); + * In which case, the hash table should have hashsize(10) elements. + * + * If you are hashing n strings (uint8_t **)k, do it like this: + * for (i = 0, h = 0; i < n; ++i) h = hashlittle(k[i], len[i], h); + * + * By Bob Jenkins, 2006. bob_jenkins@burtleburtle.net. You may use this + * code any way you wish, private, educational, or commercial. It's free. + * + * Use for hash table lookup, or anything where one collision in 2^^32 is + * acceptable. Do NOT use for cryptographic purposes. + */ +static +uint32_t hashlittle(const void *key, size_t length, uint32_t initval) +{ + uint32_t a, b, c; /* internal state */ + union { + const void *ptr; + size_t i; + } u; + + /* Set up the internal state */ + a = b = c = 0xdeadbeef + ((uint32_t)length) + initval; + + u.ptr = key; + if (HASH_LITTLE_ENDIAN && ((u.i & 0x3) == 0)) { + const uint32_t *k = (const uint32_t *) key; /* read 32-bit chunks */ + + /*------ all but last block: aligned reads and affect 32 bits of (a,b,c) */ + while (length > 12) { + a += k[0]; + b += k[1]; + c += k[2]; + mix(a, b, c); + length -= 12; + k += 3; + } + + /*----------------------------- handle the last (probably partial) block */ + /* + * "k[2]&0xffffff" actually reads beyond the end of the string, but + * then masks off the part it's not allowed to read. Because the + * string is aligned, the masked-off tail is in the same word as the + * rest of the string. Every machine with memory protection I've seen + * does it on word boundaries, so is OK with this. But VALGRIND will + * still catch it and complain. The masking trick does make the hash + * noticably faster for short strings (like English words). + */ +#ifndef VALGRIND + + switch (length) { + case 12: c+=k[2]; b+=k[1]; a+=k[0]; break; + case 11: c+=k[2]&0xffffff; b+=k[1]; a+=k[0]; break; + case 10: c+=k[2]&0xffff; b+=k[1]; a+=k[0]; break; + case 9 : c+=k[2]&0xff; b+=k[1]; a+=k[0]; break; + case 8 : b+=k[1]; a+=k[0]; break; + case 7 : b+=k[1]&0xffffff; a+=k[0]; break; + case 6 : b+=k[1]&0xffff; a+=k[0]; break; + case 5 : b+=k[1]&0xff; a+=k[0]; break; + case 4 : a+=k[0]; break; + case 3 : a+=k[0]&0xffffff; break; + case 2 : a+=k[0]&0xffff; break; + case 1 : a+=k[0]&0xff; break; + case 0 : return c; /* zero length strings require no mixing */ + } + +#else /* make valgrind happy */ + { + const uint8_t *k8; + + k8 = (const uint8_t *) k; + switch (length) { + case 12: c+=k[2]; b+=k[1]; a+=k[0]; break; + case 11: c+=((uint32_t) k8[10])<<16; /* fall through */ + case 10: c+=((uint32_t) k8[9])<<8; /* fall through */ + case 9 : c+=k8[8]; /* fall through */ + case 8 : b+=k[1]; a+=k[0]; break; + case 7 : b+=((uint32_t) k8[6])<<16; /* fall through */ + case 6 : b+=((uint32_t) k8[5])<<8; /* fall through */ + case 5 : b+=k8[4]; /* fall through */ + case 4 : a+=k[0]; break; + case 3 : a+=((uint32_t) k8[2])<<16; /* fall through */ + case 2 : a+=((uint32_t) k8[1])<<8; /* fall through */ + case 1 : a+=k8[0]; break; + case 0 : return c; + } + } +#endif /* !valgrind */ + + } else if (HASH_LITTLE_ENDIAN && ((u.i & 0x1) == 0)) { + const uint16_t *k = (const uint16_t *) key; /* read 16-bit chunks */ + const uint8_t *k8; + + /*--------------- all but last block: aligned reads and different mixing */ + while (length > 12) + { + a += k[0] + (((uint32_t) k[1])<<16); + b += k[2] + (((uint32_t) k[3])<<16); + c += k[4] + (((uint32_t) k[5])<<16); + mix(a, b, c); + length -= 12; + k += 6; + } + + /*----------------------------- handle the last (probably partial) block */ + k8 = (const uint8_t *) k; + switch(length) + { + case 12: c+=k[4]+(((uint32_t) k[5])<<16); + b+=k[2]+(((uint32_t) k[3])<<16); + a+=k[0]+(((uint32_t) k[1])<<16); + break; + case 11: c+=((uint32_t) k8[10])<<16; /* fall through */ + case 10: c+=k[4]; + b+=k[2]+(((uint32_t) k[3])<<16); + a+=k[0]+(((uint32_t) k[1])<<16); + break; + case 9 : c+=k8[8]; /* fall through */ + case 8 : b+=k[2]+(((uint32_t) k[3])<<16); + a+=k[0]+(((uint32_t) k[1])<<16); + break; + case 7 : b+=((uint32_t) k8[6])<<16; /* fall through */ + case 6 : b+=k[2]; + a+=k[0]+(((uint32_t) k[1])<<16); + break; + case 5 : b+=k8[4]; /* fall through */ + case 4 : a+=k[0]+(((uint32_t) k[1])<<16); + break; + case 3 : a+=((uint32_t) k8[2])<<16; /* fall through */ + case 2 : a+=k[0]; + break; + case 1 : a+=k8[0]; + break; + case 0 : return c; /* zero length requires no mixing */ + } + + } else { /* need to read the key one byte at a time */ + const uint8_t *k = (const uint8_t *)key; + + /*--------------- all but the last block: affect some 32 bits of (a, b, c) */ + while (length > 12) { + a += k[0]; + a += ((uint32_t) k[1])<<8; + a += ((uint32_t) k[2])<<16; + a += ((uint32_t) k[3])<<24; + b += k[4]; + b += ((uint32_t) k[5])<<8; + b += ((uint32_t) k[6])<<16; + b += ((uint32_t) k[7])<<24; + c += k[8]; + c += ((uint32_t) k[9])<<8; + c += ((uint32_t) k[10])<<16; + c += ((uint32_t) k[11])<<24; + mix(a,b,c); + length -= 12; + k += 12; + } + + /*-------------------------------- last block: affect all 32 bits of (c) */ + switch (length) { /* all the case statements fall through */ + case 12: c+=((uint32_t) k[11])<<24; + case 11: c+=((uint32_t) k[10])<<16; + case 10: c+=((uint32_t) k[9])<<8; + case 9 : c+=k[8]; + case 8 : b+=((uint32_t) k[7])<<24; + case 7 : b+=((uint32_t) k[6])<<16; + case 6 : b+=((uint32_t) k[5])<<8; + case 5 : b+=k[4]; + case 4 : a+=((uint32_t) k[3])<<24; + case 3 : a+=((uint32_t) k[2])<<16; + case 2 : a+=((uint32_t) k[1])<<8; + case 1 : a+=k[0]; + break; + case 0 : return c; + } + } + + final(a, b, c); + return c; +} + +static inline +uint32_t jhash(const void *key, size_t length, uint32_t seed) +{ + return hashlittle(key, length, seed); +} + +#endif /* _JHASH_H */