From 1aa9dd9e4560d9b58c130bd205a4b369650bad04 Mon Sep 17 00:00:00 2001 From: Hanspeter Portner Date: Fri, 5 May 2023 14:18:51 +0200 Subject: [PATCH] Squashed 'subprojects/varchunk/' content from commit 42c947e3 git-subtree-dir: subprojects/varchunk git-subtree-split: 42c947e3fc14a7cc20c2ac41f568306cca0085b1 --- .build.yml | 17 +++ .gitignore | 5 + LICENSES/Artistic-2.0.txt | 85 +++++++++++ LICENSES/CC0-1.0.txt | 121 ++++++++++++++++ README.md | 104 ++++++++++++++ meson.build | 57 ++++++++ meson_options.txt | 4 + src/varchunk.c | 295 ++++++++++++++++++++++++++++++++++++++ test/test.c | 242 +++++++++++++++++++++++++++++++ varchunk/varchunk.h | 79 ++++++++++ 10 files changed, 1009 insertions(+) create mode 100644 .build.yml create mode 100644 .gitignore create mode 100644 LICENSES/Artistic-2.0.txt create mode 100644 LICENSES/CC0-1.0.txt create mode 100644 README.md create mode 100644 meson.build create mode 100644 meson_options.txt create mode 100644 src/varchunk.c create mode 100644 test/test.c create mode 100644 varchunk/varchunk.h diff --git a/.build.yml b/.build.yml new file mode 100644 index 0000000..f76c316 --- /dev/null +++ b/.build.yml @@ -0,0 +1,17 @@ +# SPDX-FileCopyrightText: Hanspeter Portner +# SPDX-License-Identifier: CC0-1.0 + +image: alpine/latest +packages: + - reuse + - meson +tasks: + - setup: | + cd varchunk + meson setup build + - build: | + cd varchunk + ninja -C build + - test: | + cd varchunk + ninja -C build test diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..cfb9f13 --- /dev/null +++ b/.gitignore @@ -0,0 +1,5 @@ +# SPDX-FileCopyrightText: Hanspeter Portner +# SPDX-License-Identifier: CC0-1.0 + +tags +*.taghl diff --git a/LICENSES/Artistic-2.0.txt b/LICENSES/Artistic-2.0.txt new file mode 100644 index 0000000..eb2e968 --- /dev/null +++ b/LICENSES/Artistic-2.0.txt @@ -0,0 +1,85 @@ +The Artistic License 2.0 + +Copyright (c) 2000-2006, The Perl Foundation. + +Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. + +Preamble + +This license establishes the terms under which a given free software Package may be copied, modified, distributed, and/or redistributed. 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Affirmer understands and acknowledges that Creative Commons is not a + party to this document and has no duty or obligation with respect to + this CC0 or use of the Work. diff --git a/README.md b/README.md new file mode 100644 index 0000000..e0f593c --- /dev/null +++ b/README.md @@ -0,0 +1,104 @@ + +# Varchunk + +## Ringbuffer optimized for realtime event handling + +[![builds.sr.ht status](https://builds.open-music-kontrollers.ch/~hp/varchunk/.svg)](https://builds.open-music-kontrollers.ch/~hp/varchunk/?) + +### Properties + +* Is realtime-safe +* Is lock-free +* Supports variably sized chunks +* Supports contiguous memory chunks +* Supports zero copy operation +* Uses a simplistic API + +### Build / test + + git clone https://git.open-music-kontrollers.ch/~hp/varchunk + cd varchunk + meson build + cd build + ninja -j4 + ninja test + +### Dependencies + +#### Optional + +* [REUSE](https://git.fsfe.org/reuse/tool) (tool for compliance with the REUSE recommendations) + +### Usage + + #include + #include + + static void * + producer_main(void *arg) + { + varchunk_t *varchunk = arg; + void *ptr; + const size_t towrite = sizeof(uint32_t); + uint32_t counter = 0; + + while(counter <= 1000000) + { + if( (ptr = varchunk_write_request(varchunk, towrite)) ) + { + // write 'towrite' bytes to 'ptr' + *(uint32_t *)ptr = counter++; + varchunk_write_advance(varchunk, towrite); + } + } + + return NULL; + } + + static void * + consumer_main(void *arg) + { + varchunk_t *varchunk = arg; + const void *ptr; + size_t toread; + + while(1) + { + if( (ptr = varchunk_read_request(varchunk, &toread)) ) + { + // read 'toread' bytes from 'ptr' + if(*(uint32_t *)ptr >= 1000000) + break; + varchunk_read_advance(varchunk); + } + } + + return NULL; + } + + int + main(int argc, char **argv) + { + if(!varchunk_is_lock_free()) + return -1; + + pthread_t producer; + pthread_t consumer; + varchunk_t *varchunk = varchunk_new(8192, true); + if(!varchunk) + return -1; + + pthread_create(&consumer, NULL, consumer_main, varchunk); + pthread_create(&producer, NULL, producer_main, varchunk); + + pthread_join(producer, NULL); + pthread_join(consumer, NULL); + + varchunk_free(varchunk); + + return 0; + } + diff --git a/meson.build b/meson.build new file mode 100644 index 0000000..1ae9a38 --- /dev/null +++ b/meson.build @@ -0,0 +1,57 @@ +# SPDX-FileCopyrightText: Hanspeter Portner +# SPDX-License-Identifier: CC0-1.0 + +project('varchunk', 'c', default_options : [ + 'buildtype=release', + 'warning_level=3', + 'werror=false', + 'b_lto=true', + 'c_std=c11']) + +reuse = find_program('reuse', required : false) + +add_project_arguments('-D_GNU_SOURCE', language : 'c') + +cc = meson.get_compiler('c') + +thread_dep = dependency('threads') + +lib_deps = [] + +lib_incs = [] +lib_incs += include_directories('') + +lib_srcs = [] +lib_srcs += join_paths('src', 'varchunk.c') + +if host_machine.system() == 'linux' + rt_dep = cc.find_library('rt') + lib_deps += rt_dep +endif + +varchunk = declare_dependency( + include_directories : lib_incs, + dependencies : lib_deps, + sources : lib_srcs) + +test_deps = [] +test_deps += varchunk +test_deps += thread_dep + +test_srcs = [] +test_srcs += join_paths('test', 'test.c') + +test_varchunk = executable('Test', test_srcs, + dependencies : test_deps, + install : false) + +test('Test', test_varchunk, + args : ['100000'], + timeout : 360) # seconds + +if reuse.found() + test('REUSE', reuse, args : [ + '--root', meson.current_source_dir(), + 'lint' + ]) +endif diff --git a/meson_options.txt b/meson_options.txt new file mode 100644 index 0000000..13a6807 --- /dev/null +++ b/meson_options.txt @@ -0,0 +1,4 @@ +# SPDX-FileCopyrightText: Hanspeter Portner +# SPDX-License-Identifier: CC0-1.0 + +option('version', type : 'string', value : '0.1.135') diff --git a/src/varchunk.c b/src/varchunk.c new file mode 100644 index 0000000..3ae8835 --- /dev/null +++ b/src/varchunk.c @@ -0,0 +1,295 @@ +/* + * SPDX-FileCopyrightText: Hanspeter Portner + * SPDX-License-Identifier: Artistic-2.0 + */ + +#include + +#if !defined(_WIN32) +# include // mlock +#endif + +#include + +#define VARCHUNK_PAD(SIZE) ( ( (size_t)(SIZE) + 7U ) & ( ~7U ) ) + +bool +varchunk_is_lock_free(void) +{ + varchunk_t varchunk; + + return atomic_is_lock_free(&varchunk.head) + && atomic_is_lock_free(&varchunk.tail); +} + +size_t +varchunk_body_size(size_t minimum) +{ + size_t size = 1; + while(size < minimum) + size <<= 1; // assure size to be a power of 2 + return size; +} + +void +varchunk_init(varchunk_t *varchunk, size_t body_size, bool release_and_acquire) +{ + varchunk->acquire = release_and_acquire + ? memory_order_acquire + : memory_order_relaxed; + varchunk->release = release_and_acquire + ? memory_order_release + : memory_order_relaxed; + + atomic_init(&varchunk->head, 0); + atomic_init(&varchunk->tail, 0); + + varchunk->size = body_size; + varchunk->mask = varchunk->size - 1; +} + +varchunk_t * +varchunk_new(size_t minimum, bool release_and_acquire) +{ + varchunk_t *varchunk = NULL; + + const size_t body_size = varchunk_body_size(minimum); + const size_t total_size = sizeof(varchunk_t) + body_size; + +#if defined(_WIN32) + varchunk = _aligned_malloc(total_size, sizeof(varchunk_elmnt_t)); +#else + posix_memalign((void **)&varchunk, sizeof(varchunk_elmnt_t), total_size); + mlock(varchunk, total_size); // prevent memory from being flushed to disk +#endif + + if(varchunk) + varchunk_init(varchunk, body_size, release_and_acquire); + + return varchunk; +} + +void +varchunk_free(varchunk_t *varchunk) +{ + if(varchunk) + { +#if !defined(_WIN32) + munlock(varchunk->buf, varchunk->size); +#endif + free(varchunk); + } +} + +static inline void +_varchunk_write_advance_raw(varchunk_t *varchunk, size_t head, size_t written) +{ + // only producer is allowed to advance write head + const size_t new_head = (head + written) & varchunk->mask; + atomic_store_explicit(&varchunk->head, new_head, varchunk->release); +} + +void * +varchunk_write_request_max(varchunk_t *varchunk, size_t minimum, size_t *maximum) +{ + assert(varchunk); + + size_t space; // size of writable buffer + size_t end; // virtual end of writable buffer + const size_t head = atomic_load_explicit(&varchunk->head, memory_order_relaxed); // read head + const size_t tail = atomic_load_explicit(&varchunk->tail, varchunk->acquire); // read tail (consumer modifies it any time) + const size_t padded = 2*sizeof(varchunk_elmnt_t) + VARCHUNK_PAD(minimum); + + // calculate writable space + if(head > tail) + space = ((tail - head + varchunk->size) & varchunk->mask) - 1; + else if(head < tail) + space = (tail - head) - 1; + else // head == tail + space = varchunk->size - 1; + end = head + space; + + if(end > varchunk->size) // available region wraps over at end of buffer + { + // get first part of available buffer + uint8_t *buf1 = varchunk->buf + head; + const size_t len1 = varchunk->size - head; + + if(len1 < padded) // not enough space left on first part of buffer + { + // get second part of available buffer + uint8_t *buf2 = varchunk->buf; + const size_t len2 = end & varchunk->mask; + + if(len2 < padded) // not enough space left on second buffer, either + { + varchunk->rsvd = 0; + varchunk->gapd = 0; + if(maximum) + *maximum = varchunk->rsvd; + return NULL; + } + else // enough space left on second buffer, use it! + { + varchunk->rsvd = len2; + varchunk->gapd = len1; + if(maximum) + *maximum = varchunk->rsvd; + return buf2 + sizeof(varchunk_elmnt_t); + } + } + else // enough space left on first part of buffer, use it! + { + varchunk->rsvd = len1; + varchunk->gapd = 0; + if(maximum) + *maximum = varchunk->rsvd; + return buf1 + sizeof(varchunk_elmnt_t); + } + } + else // available region is contiguous + { + uint8_t *buf = varchunk->buf + head; + + if(space < padded) // no space left on contiguous buffer + { + varchunk->rsvd = 0; + varchunk->gapd = 0; + if(maximum) + *maximum = varchunk->rsvd; + return NULL; + } + else // enough space left on contiguous buffer, use it! + { + varchunk->rsvd = space; + varchunk->gapd = 0; + if(maximum) + *maximum = varchunk->rsvd; + return buf + sizeof(varchunk_elmnt_t); + } + } +} + +void * +varchunk_write_request(varchunk_t *varchunk, size_t minimum) +{ + return varchunk_write_request_max(varchunk, minimum, NULL); +} + +void +varchunk_write_advance(varchunk_t *varchunk, size_t written) +{ + assert(varchunk); + // fail miserably if stupid programmer tries to write more than rsvd + assert(written <= varchunk->rsvd); + + // write elmnt header at head + const size_t head = atomic_load_explicit(&varchunk->head, memory_order_relaxed); + if(varchunk->gapd > 0) + { + // fill end of first buffer with gap + varchunk_elmnt_t *elmnt = (varchunk_elmnt_t *)(varchunk->buf + head); + elmnt->size = varchunk->gapd - sizeof(varchunk_elmnt_t); + elmnt->gap = 1; + + // fill written element header + elmnt = (void *)varchunk->buf; + elmnt->size = written; + elmnt->gap = 0; + } + else // varchunk->gapd == 0 + { + // fill written element header + varchunk_elmnt_t *elmnt = (varchunk_elmnt_t *)(varchunk->buf + head); + elmnt->size = written; + elmnt->gap = 0; + } + + // advance write head + _varchunk_write_advance_raw(varchunk, head, + varchunk->gapd + sizeof(varchunk_elmnt_t) + VARCHUNK_PAD(written)); +} + +static inline void +_varchunk_read_advance_raw(varchunk_t *varchunk, size_t tail, size_t read) +{ + // only consumer is allowed to advance read tail + const size_t new_tail = (tail + read) & varchunk->mask; + atomic_store_explicit(&varchunk->tail, new_tail, varchunk->release); +} + +const void * +varchunk_read_request(varchunk_t *varchunk, size_t *toread) +{ + assert(varchunk); + size_t space; // size of available buffer + const size_t tail = atomic_load_explicit(&varchunk->tail, memory_order_relaxed); // read tail + const size_t head = atomic_load_explicit(&varchunk->head, varchunk->acquire); // read head (producer modifies it any time) + + // calculate readable space + if(head > tail) + space = head - tail; + else + space = (head - tail + varchunk->size) & varchunk->mask; + + if(space > 0) // there may be chunks available for reading + { + const size_t end = tail + space; // virtual end of available buffer + + if(end > varchunk->size) // available buffer wraps around at end + { + // first part of available buffer + const uint8_t *buf1 = varchunk->buf + tail; + const size_t len1 = varchunk->size - tail; + const varchunk_elmnt_t *elmnt = (const varchunk_elmnt_t *)buf1; + + if(elmnt->gap) // gap elmnt? + { + // skip gap + _varchunk_read_advance_raw(varchunk, tail, len1); + + // second part of available buffer + const uint8_t *buf2 = varchunk->buf; + // there will always be at least on element after a gap + elmnt = (const varchunk_elmnt_t *)buf2; + + *toread = elmnt->size; + return buf2 + sizeof(varchunk_elmnt_t); + } + else // valid chunk, use it! + { + *toread = elmnt->size; + return buf1 + sizeof(varchunk_elmnt_t); + } + } + else // available buffer is contiguous + { + // get buffer + const uint8_t *buf = varchunk->buf + tail; + const varchunk_elmnt_t *elmnt = (const varchunk_elmnt_t *)buf; + + *toread = elmnt->size; + return buf + sizeof(varchunk_elmnt_t); + } + } + else // no chunks available aka empty buffer + { + *toread = 0; + return NULL; + } +} + +void +varchunk_read_advance(varchunk_t *varchunk) +{ + assert(varchunk); + // get elmnt header from tail (for size) + const size_t tail = atomic_load_explicit(&varchunk->tail, memory_order_relaxed); + const varchunk_elmnt_t *elmnt = (const varchunk_elmnt_t *)(varchunk->buf + tail); + + // advance read tail + _varchunk_read_advance_raw(varchunk, tail, + sizeof(varchunk_elmnt_t) + VARCHUNK_PAD(elmnt->size)); +} + +#undef VARCHUNK_PAD diff --git a/test/test.c b/test/test.c new file mode 100644 index 0000000..be2cd1e --- /dev/null +++ b/test/test.c @@ -0,0 +1,242 @@ +/* + * SPDX-FileCopyrightText: Hanspeter Portner + * SPDX-License-Identifier: Artistic-2.0 + */ + +#include +#include +#include +#include +#include +#include + +#include + +#if !defined(_WIN32) +# include +# include +# include +# include +# define VARCHUNK_USE_SHARED_MEM + +static const struct timespec req = { + .tv_sec = 0, + .tv_nsec = 1 +}; +#endif + +static uint64_t iterations = 10000000; +#define THRESHOLD (RAND_MAX / 256) +#define PAD(SIZE) ( ( (size_t)(SIZE) + 7U ) & ( ~7U ) ) + +static void * +producer_main(void *arg) +{ + varchunk_t *varchunk = arg; + uint8_t *ptr; + const uint8_t *end; + size_t written; + uint64_t cnt = 0; + + while(cnt < iterations) + { +#if !defined(_WIN32) + if(rand() < THRESHOLD) + { + nanosleep(&req, NULL); + } +#endif + + written = PAD(rand() * 1024.f / RAND_MAX); + + size_t maximum; + if( (ptr = varchunk_write_request_max(varchunk, written, &maximum)) ) + { + assert(maximum >= written); + end = ptr + written; + for(uint8_t *src=ptr; srcname = strdup(name); + if(!varchunk_shm->name) + { + return -1; + } + + bool is_first = true; + varchunk_shm->fd = shm_open(varchunk_shm->name, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR); + if(varchunk_shm->fd == -1) + { + is_first = false; + varchunk_shm->fd = shm_open(varchunk_shm->name, O_RDWR , S_IRUSR | S_IWUSR); + } + if(varchunk_shm->fd == -1) + { + free(varchunk_shm->name); + return -1; + } + + if( (ftruncate(varchunk_shm->fd, total_size) == -1) + || ((varchunk_shm->varchunk = mmap(NULL, total_size, PROT_READ | PROT_WRITE, + MAP_SHARED, varchunk_shm->fd, 0)) == MAP_FAILED) ) + { + shm_unlink(varchunk_shm->name); + close(varchunk_shm->fd); + free(varchunk_shm->name); + return -1; + } + + if(is_first) + { + varchunk_init(varchunk_shm->varchunk, body_size, release_and_acquire); + } + + return 0; +} + +static void +varchunk_shm_deinit(varchunk_shm_t *varchunk_shm) +{ + const size_t total_size = sizeof(varchunk_t) + varchunk_shm->varchunk->size; + + munmap(varchunk_shm->varchunk, total_size); + shm_unlink(varchunk_shm->name); + close(varchunk_shm->fd); + free(varchunk_shm->name); +} + +static void +test_shared() +{ + const char *name = "/varchunk_shm_test"; + pid_t pid = fork(); + + assert(pid != -1); + + if(pid == 0) // child + { + varchunk_shm_t varchunk_shm; + assert(varchunk_shm_init(&varchunk_shm, name, 8192, true) == 0); + + consumer_main(varchunk_shm.varchunk); + + varchunk_shm_deinit(&varchunk_shm); + } + else // parent + { + varchunk_shm_t varchunk_shm; + assert(varchunk_shm_init(&varchunk_shm, name, 8192, true) == 0); + + producer_main(varchunk_shm.varchunk); + + varchunk_shm_deinit(&varchunk_shm); + } +} +#endif + +int +main(int argc, char **argv) +{ +#if !defined(_WIN32) + const int seed = time(NULL); + srand(seed); +#endif + + if(argc >= 2) + { + iterations = atoi(argv[1]); + } + + assert(varchunk_is_lock_free()); + + test_threaded(); + +#if defined(VARCHUNK_USE_SHARED_MEM) + test_shared(); +#endif + + return 0; +} diff --git a/varchunk/varchunk.h b/varchunk/varchunk.h new file mode 100644 index 0000000..4291959 --- /dev/null +++ b/varchunk/varchunk.h @@ -0,0 +1,79 @@ +/* + * SPDX-FileCopyrightText: Hanspeter Portner + * SPDX-License-Identifier: Artistic-2.0 + */ + +#ifndef _VARCHUNK_H +#define _VARCHUNK_H + +#ifdef __cplusplus +extern "C" { +#endif + +#include +#include +#include +#include + +/***************************************************************************** + * API START + *****************************************************************************/ + +typedef struct _varchunk_elmnt_t varchunk_elmnt_t; +typedef struct _varchunk_t varchunk_t; + +struct _varchunk_elmnt_t { + uint32_t size; + uint32_t gap; +}; + +struct _varchunk_t { + size_t size; + size_t mask; + size_t rsvd; + size_t gapd; + + memory_order acquire; + memory_order release; + + atomic_size_t head; + atomic_size_t tail; + + uint8_t buf [] __attribute__((aligned(sizeof(varchunk_elmnt_t)))); +}; + +bool +varchunk_is_lock_free(void); + +size_t +varchunk_body_size(size_t minimum); + +varchunk_t * +varchunk_new(size_t minimum, bool release_and_acquire); + +void +varchunk_free(varchunk_t *varchunk); + +void +varchunk_init(varchunk_t *varchunk, size_t body_size, bool release_and_acquire); + +void * +varchunk_write_request_max(varchunk_t *varchunk, size_t minimum, size_t *maximum); + +void * +varchunk_write_request(varchunk_t *varchunk, size_t minimum); + +void +varchunk_write_advance(varchunk_t *varchunk, size_t written); + +const void * +varchunk_read_request(varchunk_t *varchunk, size_t *toread); + +void +varchunk_read_advance(varchunk_t *varchunk); + +#ifdef __cplusplus +} +#endif + +#endif //_VARCHUNK_H -- 2.38.5