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ck_pflock: Phase-fair read-write lock implementation.

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John Wittrock has contributed a phase-fair reader-writer
lock implementation. These locks allow phase fairness
guarantees between readers and writers. This work includes
additional changes and clean-up.

Follow-up work is expected.

Thanks to John Wittrock for patches and Professor Gabriel
Parmer (http://www.seas.gwu.edu/~gparmer/) for advising.
ck_pring
Samy Al Bahra 12 years ago
parent 7d3fd9d227
commit 54845bb8e7
7 changed files with 565 additions and 0 deletions
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141
include/ck_pflock.h
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/*
* Copyright 2013 John Wittrock.
* Copyright 2013 Samy Al Bahra.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXCK_PFLOCK_PRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _CK_PFLOCK_H
#define _CK_PFLOCK_H
/*
* This is a naive implementation of phase-fair locks derived
* from the work described in:
* Brandenburg, B. and Anderson, J. 2010. Spin-Based
* Reader-Writer Synchronization for Multiprocessor Real-Time Systems
*/
#include <ck_cc.h>
#include <ck_pr.h>
struct ck_pflock {
uint32_t rin;
uint32_t rout;
uint32_t win;
uint32_t wout;
};
typedef struct ck_pflock ck_pflock_t;
#define CK_PFLOCK_LSB 0xFFFFFFF0
#define CK_PFLOCK_RINC 0x100 /* Reader increment value. */
#define CK_PFLOCK_WBITS 0x3 /* Writer bits in reader. */
#define CK_PFLOCK_PRES 0x2 /* Writer present bit. */
#define CK_PFLOCK_PHID 0x1 /* Phase ID bit. */
#define CK_PFLOCK_INITIALIZER {0, 0, 0, 0}
CK_CC_INLINE static void
ck_pflock_init(struct ck_pflock *pf)
{
pf->rin = 0;
pf->rout = 0;
pf->win = 0;
pf->wout = 0;
ck_pr_fence_memory();
return;
}
CK_CC_INLINE static void
ck_pflock_write_unlock(ck_pflock_t *pf)
{
ck_pr_fence_memory();
/* Migrate from write phase to read phase. */
ck_pr_and_32(&pf->rin, CK_PFLOCK_LSB);
/* Allow other writers to continue. */
ck_pr_faa_32(&pf->wout, 1);
return;
}
CK_CC_INLINE static void
ck_pflock_write_lock(ck_pflock_t *pf)
{
uint32_t ticket;
/* Acquire ownership of write-phase. */
ticket = ck_pr_faa_32(&pf->win, 1);
while (ck_pr_load_32(&pf->wout) != ticket)
ck_pr_stall();
/*
* Acquire ticket on read-side in order to allow them
* to flush. Indicates to any incoming reader that a
* write-phase is pending.
*/
ticket = ck_pr_faa_32(&pf->rin,
(ticket & CK_PFLOCK_PHID) | CK_PFLOCK_PRES);
/* Wait for any pending readers to flush. */
while (ck_pr_load_32(&pf->rout) != ticket)
ck_pr_stall();
ck_pr_fence_memory();
return;
}
CK_CC_INLINE static void
ck_pflock_read_unlock(ck_pflock_t *pf)
{
ck_pr_fence_memory();
ck_pr_faa_32(&pf->rout, CK_PFLOCK_RINC);
return;
}
CK_CC_INLINE static void
ck_pflock_read_lock(ck_pflock_t *pf)
{
uint32_t w;
/*
* If no writer is present, then the operation has completed
* successfully.
*/
w = ck_pr_faa_32(&pf->rin, CK_PFLOCK_RINC) & CK_PFLOCK_WBITS;
if (w == 0)
return;
/* Wait for current write phase to complete. */
while ((ck_pr_load_32(&pf->rin) & CK_PFLOCK_WBITS) == w)
ck_pr_stall();
/* Acquire semantics. */
ck_pr_fence_load();
return;
}
#endif /* _CK_PFLOCK_H */

4
regressions/Makefile
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@ -47,6 +47,8 @@ all:
$(MAKE) -C ./ck_ring/benchmark all
$(MAKE) -C ./ck_rwlock/validate all
$(MAKE) -C ./ck_rwlock/benchmark all
$(MAKE) -C ./ck_pflock/validate all
$(MAKE) -C ./ck_pflock/benchmark all
$(MAKE) -C ./ck_hp/validate all
$(MAKE) -C ./ck_hp/benchmark all
$(MAKE) -C ./ck_bag/validate all
@ -79,6 +81,8 @@ clean:
$(MAKE) -C ./ck_ring/benchmark clean
$(MAKE) -C ./ck_rwlock/validate clean
$(MAKE) -C ./ck_rwlock/benchmark clean
$(MAKE) -C ./ck_pflock/validate clean
$(MAKE) -C ./ck_pflock/benchmark clean
$(MAKE) -C ./ck_hp/validate clean
$(MAKE) -C ./ck_hp/benchmark clean
$(MAKE) -C ./ck_bag/validate clean

17
regressions/ck_pflock/benchmark/Makefile
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.PHONY: clean distribution
OBJECTS=latency throughput
all: $(OBJECTS)
latency: latency.c ../../../include/ck_rwlock.h
$(CC) $(CFLAGS) -o latency latency.c
throughput: throughput.c ../../../include/ck_rwlock.h
$(CC) $(CFLAGS) -o throughput throughput.c
clean:
rm -rf *.dSYM *~ *.o $(OBJECTS)
include ../../../build/regressions.build
CFLAGS+=$(PTHREAD_CFLAGS) -D_GNU_SOURCE

72
regressions/ck_pflock/benchmark/latency.c
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/*
* Copyright 2011-2013 Samy Al Bahra.
* Copyright 2013 John Wittrock.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHEPFISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <ck_pflock.h>
#include <inttypes.h>
#include <stdio.h>
#include "../../common.h"
#ifndef STEPS
#define STEPS 1000000
#endif
int
main(void)
{
uint64_t s_b, e_b, i;
ck_pflock_t pflock = CK_PFLOCK_INITIALIZER;
for (i = 0; i < STEPS; i++) {
ck_pflock_write_lock(&pflock);
ck_pflock_write_unlock(&pflock);
}
s_b = rdtsc();
for (i = 0; i < STEPS; i++) {
ck_pflock_write_lock(&pflock);
ck_pflock_write_unlock(&pflock);
}
e_b = rdtsc();
printf("WRITE: pflock %15" PRIu64 "\n", (e_b - s_b) / STEPS);
for (i = 0; i < STEPS; i++) {
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
}
s_b = rdtsc();
for (i = 0; i < STEPS; i++) {
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
}
e_b = rdtsc();
printf("READ: pflock %15" PRIu64 "\n", (e_b - s_b) / STEPS);
return 0;
}

163
regressions/ck_pflock/benchmark/throughput.c
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/*
* Copyright 2011-2013 Samy Al Bahra.
* Copyright 2013 John Wittrock.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHEPFISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <ck_pflock.h>
#include <inttypes.h>
#include <pthread.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include "../../common.h"
#ifndef STEPS
#define STEPS 1000000
#endif
static int barrier;
static int threads;
static unsigned int flag CK_CC_CACHELINE;
static ck_pflock_t pflock = CK_PFLOCK_INITIALIZER;
static struct affinity affinity;
static void *
thread_pflock(void *pun)
{
uint64_t s_b, e_b, a, i;
uint64_t *value = pun;
if (aff_iterate(&affinity) != 0) {
perror("ERROR: Could not affine thread");
exit(EXIT_FAILURE);
}
ck_pr_inc_int(&barrier);
while (ck_pr_load_int(&barrier) != threads)
ck_pr_stall();
for (i = 1, a = 0;; i++) {
s_b = rdtsc();
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
ck_pflock_read_lock(&pflock);
ck_pflock_read_unlock(&pflock);
e_b = rdtsc();
a += (e_b - s_b) >> 4;
if (ck_pr_load_uint(&flag) == 1)
break;
}
ck_pr_inc_int(&barrier);
while (ck_pr_load_int(&barrier) != threads * 2)
ck_pr_stall();
*value = (a / i);
return NULL;
}
int
main(int argc, char *argv[])
{
int t;
pthread_t *p;
uint64_t *latency;
if (argc != 3) {
ck_error("Usage: throughput <delta> <threads>\n");
}
threads = atoi(argv[2]);
if (threads <= 0) {
ck_error("ERROR: Threads must be a value > 0.\n");
}
p = malloc(sizeof(pthread_t) * threads);
if (p == NULL) {
ck_error("ERROR: Failed to initialize thread.\n");
}
latency = malloc(sizeof(uint64_t) * threads);
if (latency == NULL) {
ck_error("ERROR: Failed to create latency buffer.\n");
}
affinity.delta = atoi(argv[1]);
affinity.request = 0;
fprintf(stderr, "Creating threads (pflock)...");
for (t = 0; t < threads; t++) {
if (pthread_create(&p[t], NULL, thread_pflock, latency + t) != 0) {
ck_error("ERROR: Could not create thread %d\n", t);
}
}
fprintf(stderr, "done\n");
common_sleep(10);
ck_pr_store_uint(&flag, 1);
fprintf(stderr, "Waiting for threads to finish acquisition regression...");
for (t = 0; t < threads; t++)
pthread_join(p[t], NULL);
fprintf(stderr, "done\n\n");
for (t = 1; t <= threads; t++)
printf("%10u %20" PRIu64 "\n", t, latency[t - 1]);
return 0;
}

17
regressions/ck_pflock/validate/Makefile
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.PHONY: check clean distribution
OBJECTS=validate
all: $(OBJECTS)
validate: validate.c ../../../include/ck_pflock.h
$(CC) $(CFLAGS) -o validate validate.c
check: all
./validate $(CORES) 1
clean:
rm -rf *.dSYM *~ *.o $(OBJECTS)
include ../../../build/regressions.build
CFLAGS+=$(PTHREAD_CFLAGS) -D_GNU_SOURCE

151
regressions/ck_pflock/validate/validate.c
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/*
* Copyright 2011-2013 Samy Al Bahra, John Wittrock.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <errno.h>
#include <inttypes.h>
#include <pthread.h>
#include <math.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>
#include <sys/time.h>
#include <ck_pr.h>
#include <ck_pflock.h>
#include "../../common.h"
#ifndef ITERATE
#define ITERATE 1000000
#endif
static struct affinity a;
static unsigned int locked;
static int nthr;
static ck_pflock_t lock = CK_PFLOCK_INITIALIZER;
static void *
thread(void *null CK_CC_UNUSED)
{
int i = ITERATE;
unsigned int l;
if (aff_iterate(&a)) {
perror("ERROR: Could not affine thread");
exit(EXIT_FAILURE);
}
while (i--) {
ck_pflock_write_lock(&lock);
{
l = ck_pr_load_uint(&locked);
if (l != 0) {
ck_error("ERROR [WR:%d]: %u != 0\n", __LINE__, l);
}
ck_pr_inc_uint(&locked);
ck_pr_inc_uint(&locked);
ck_pr_inc_uint(&locked);
ck_pr_inc_uint(&locked);
ck_pr_inc_uint(&locked);
ck_pr_inc_uint(&locked);
ck_pr_inc_uint(&locked);
ck_pr_inc_uint(&locked);
l = ck_pr_load_uint(&locked);
if (l != 8) {
ck_error("ERROR [WR:%d]: %u != 2\n", __LINE__, l);
}
ck_pr_dec_uint(&locked);
ck_pr_dec_uint(&locked);
ck_pr_dec_uint(&locked);
ck_pr_dec_uint(&locked);
ck_pr_dec_uint(&locked);
ck_pr_dec_uint(&locked);
ck_pr_dec_uint(&locked);
ck_pr_dec_uint(&locked);
l = ck_pr_load_uint(&locked);
if (l != 0) {
ck_error("ERROR [WR:%d]: %u != 0\n", __LINE__, l);
}
}
ck_pflock_write_unlock(&lock);
ck_pflock_read_lock(&lock);
{
l = ck_pr_load_uint(&locked);
if (l != 0) {
ck_error("ERROR [RD:%d]: %u != 0\n", __LINE__, l);
}
}
ck_pflock_read_unlock(&lock);
}
return NULL;
}
int
main(int argc, char *argv[])
{
pthread_t *threads;
int i;
if (argc != 3) {
ck_error("Usage: validate <number of threads> <affinity delta>\n");
}
nthr = atoi(argv[1]);
if (nthr <= 0) {
ck_error("ERROR: Number of threads must be greater than 0\n");
}
threads = malloc(sizeof(pthread_t) * nthr);
if (threads == NULL) {
ck_error("ERROR: Could not allocate thread structures\n");
}
a.delta = atoi(argv[2]);
fprintf(stderr, "Creating threads (mutual exclusion)...");
for (i = 0; i < nthr; i++) {
if (pthread_create(&threads[i], NULL, thread, NULL)) {
ck_error("ERROR: Could not create thread %d\n", i);
}
}
fprintf(stderr, "done\n");
fprintf(stderr, "Waiting for threads to finish correctness regression...");
for (i = 0; i < nthr; i++)
pthread_join(threads[i], NULL);
fprintf(stderr, "done (passed)\n");
return 0;
}
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