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146 lines
2.5 KiB
146 lines
2.5 KiB
#include <ck_bytelock.h>
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#include <ck_spinlock.h>
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#include <inttypes.h>
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#include <stdio.h>
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#ifndef STEPS
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#define STEPS 100000ULL
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#endif
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/*
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* This is a naive reader/writer spinlock.
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*/
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struct rwlock {
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unsigned int readers;
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ck_spinlock_fas_t writer;
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};
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typedef struct rwlock rwlock_t;
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static CK_CC_INLINE void
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rwlock_init(rwlock_t *rw)
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{
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ck_pr_store_uint(&rw->readers, 0);
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ck_spinlock_fas_init(&rw->writer);
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return;
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}
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static CK_CC_INLINE void
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rwlock_write_lock(rwlock_t *rw)
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{
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ck_spinlock_fas_lock(&rw->writer);
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while (ck_pr_load_uint(&rw->readers) != 0)
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ck_pr_stall();
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return;
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}
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static CK_CC_INLINE void
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rwlock_write_unlock(rwlock_t *rw)
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{
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ck_spinlock_fas_unlock(&rw->writer);
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return;
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}
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static CK_CC_INLINE void
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rwlock_read_lock(rwlock_t *rw)
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{
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for (;;) {
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while (ck_pr_load_uint(&rw->writer.value) != 0)
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ck_pr_stall();
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ck_pr_inc_uint(&rw->readers);
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if (ck_pr_load_uint(&rw->writer.value) == 0)
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break;
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ck_pr_dec_uint(&rw->readers);
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}
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return;
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}
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static CK_CC_INLINE void
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rwlock_read_unlock(rwlock_t *rw)
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{
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ck_pr_dec_uint(&rw->readers);
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return;
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}
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static inline uint64_t
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rdtsc(void)
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{
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#if defined(__x86_64__)
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uint32_t eax = 0, edx;
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__asm__ __volatile__("cpuid;"
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"rdtsc;"
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: "+a" (eax), "=d" (edx)
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:
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: "%rcx", "%rbx", "memory");
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__asm__ __volatile__("xorl %%eax, %%eax;"
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"cpuid;"
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:
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:
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: "%rax", "%rbx", "%rcx", "%rdx", "memory");
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return (((uint64_t)edx << 32) | eax);
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#endif
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return 0;
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}
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int
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main(void)
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{
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uint64_t s_b, e_b;
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uint64_t i;
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ck_bytelock_t bytelock = CK_BYTELOCK_INITIALIZER;
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rwlock_t naive;
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ck_bytelock_write_lock(&bytelock, 1);
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ck_bytelock_write_unlock(&bytelock);
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s_b = rdtsc();
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for (i = 0; i < STEPS; i++) {
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ck_bytelock_write_lock(&bytelock, 1);
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ck_bytelock_write_unlock(&bytelock);
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}
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e_b = rdtsc();
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printf("WRITE: bytelock %15" PRIu64 "\n", e_b - s_b);
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rwlock_init(&naive);
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rwlock_write_lock(&naive);
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rwlock_write_unlock(&naive);
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s_b = rdtsc();
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for (i = 0; i < STEPS; i++) {
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rwlock_write_lock(&naive);
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rwlock_write_unlock(&naive);
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}
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e_b = rdtsc();
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printf("WRITE: naive %15" PRIu64 "\n", e_b - s_b);
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s_b = rdtsc();
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for (i = 0; i < STEPS; i++) {
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ck_bytelock_read_lock(&bytelock, 1);
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ck_bytelock_read_unlock(&bytelock, 1);
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}
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e_b = rdtsc();
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printf("READ: bytelock %15" PRIu64 "\n", e_b - s_b);
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s_b = rdtsc();
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for (i = 0; i < STEPS; i++) {
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rwlock_write_lock(&naive);
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rwlock_write_unlock(&naive);
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}
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e_b = rdtsc();
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printf("READ: naive %15" PRIu64 "\n", e_b - s_b);
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return (0);
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}
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