cpp-ipc/src/prod_cons.h
2019-03-26 22:41:27 +08:00

352 lines
13 KiB
C++

#pragma once
#include <atomic>
#include <utility>
#include <cstring>
#include <type_traits>
#include "def.h"
#include "circ/elem_def.h"
namespace ipc {
////////////////////////////////////////////////////////////////
/// producer-consumer implementation
////////////////////////////////////////////////////////////////
template <typename Flag>
struct prod_cons_impl;
template <>
struct prod_cons_impl<wr<relat::single, relat::single, trans::unicast>> {
template <std::size_t DataSize, std::size_t AlignSize>
struct elem_t {
std::aligned_storage_t<DataSize, AlignSize> data_ {};
};
alignas(circ::cache_line_size) std::atomic<circ::u2_t> rd_; // read index
alignas(circ::cache_line_size) std::atomic<circ::u2_t> wt_; // write index
constexpr circ::u2_t cursor() const noexcept {
return 0;
}
template <typename W, typename F, typename E>
bool push(W* /*wrapper*/, F&& f, E* elems) {
auto cur_wt = circ::index_of(wt_.load(std::memory_order_relaxed));
if (cur_wt == circ::index_of(rd_.load(std::memory_order_acquire) - 1)) {
return false; // full
}
std::forward<F>(f)(&(elems[cur_wt].data_));
wt_.fetch_add(1, std::memory_order_release);
return true;
}
template <typename W, typename F, typename E>
bool force_push(W* wrapper, F&& f, E* elems) {
return push(wrapper, std::forward<F>(f), elems);
}
template <typename W, typename F, typename E>
bool pop(W* /*wrapper*/, circ::u2_t& /*cur*/, F&& f, E* elems) {
auto cur_rd = circ::index_of(rd_.load(std::memory_order_relaxed));
if (cur_rd == circ::index_of(wt_.load(std::memory_order_acquire))) {
return false; // empty
}
std::forward<F>(f)(&(elems[cur_rd].data_));
rd_.fetch_add(1, std::memory_order_release);
return true;
}
};
template <>
struct prod_cons_impl<wr<relat::single, relat::multi , trans::unicast>>
: prod_cons_impl<wr<relat::single, relat::single, trans::unicast>> {
template <typename W, typename F, template <std::size_t, std::size_t> class E, std::size_t DS, std::size_t AS>
bool pop(W* /*wrapper*/, circ::u2_t& /*cur*/, F&& f, E<DS, AS>* elems) {
byte_t buff[DS];
for (unsigned k = 0;;) {
auto cur_rd = rd_.load(std::memory_order_relaxed);
if (circ::index_of(cur_rd) ==
circ::index_of(wt_.load(std::memory_order_acquire))) {
return false; // empty
}
std::memcpy(buff, &(elems[circ::index_of(cur_rd)].data_), sizeof(buff));
if (rd_.compare_exchange_weak(cur_rd, cur_rd + 1, std::memory_order_release)) {
std::forward<F>(f)(buff);
return true;
}
ipc::yield(k);
}
}
};
template <>
struct prod_cons_impl<wr<relat::multi , relat::multi, trans::unicast>>
: prod_cons_impl<wr<relat::single, relat::multi, trans::unicast>> {
using flag_t = std::uint64_t;
template <std::size_t DataSize, std::size_t AlignSize>
struct elem_t {
std::aligned_storage_t<DataSize, AlignSize> data_ {};
std::atomic<flag_t> f_ct_ { 0 }; // commit flag
};
alignas(circ::cache_line_size) std::atomic<circ::u2_t> ct_; // commit index
template <typename W, typename F, typename E>
bool push(W* /*wrapper*/, F&& f, E* elems) {
circ::u2_t cur_ct, nxt_ct;
for (unsigned k = 0;;) {
cur_ct = ct_.load(std::memory_order_relaxed);
if (circ::index_of(nxt_ct = cur_ct + 1) ==
circ::index_of(rd_.load(std::memory_order_acquire))) {
return false; // full
}
if (ct_.compare_exchange_weak(cur_ct, nxt_ct, std::memory_order_release)) {
break;
}
ipc::yield(k);
}
auto* el = elems + circ::index_of(cur_ct);
std::forward<F>(f)(&(el->data_));
// set flag & try update wt
el->f_ct_.store(~static_cast<flag_t>(cur_ct), std::memory_order_release);
while (1) {
auto cac_ct = el->f_ct_.load(std::memory_order_acquire);
if (cur_ct != wt_.load(std::memory_order_acquire)) {
return true;
}
if ((~cac_ct) != cur_ct) {
return true;
}
if (!el->f_ct_.compare_exchange_strong(cac_ct, 0, std::memory_order_relaxed)) {
return true;
}
wt_.store(nxt_ct, std::memory_order_release);
cur_ct = nxt_ct;
nxt_ct = cur_ct + 1;
el = elems + circ::index_of(cur_ct);
}
return true;
}
template <typename W, typename F, typename E>
bool force_push(W* wrapper, F&& f, E* elems) {
return push(wrapper, std::forward<F>(f), elems); /* TBD */
}
template <typename W, typename F, template <std::size_t, std::size_t> class E, std::size_t DS, std::size_t AS>
bool pop(W* /*wrapper*/, circ::u2_t& /*cur*/, F&& f, E<DS, AS>* elems) {
byte_t buff[DS];
for (unsigned k = 0;;) {
auto cur_rd = rd_.load(std::memory_order_relaxed);
auto cur_wt = wt_.load(std::memory_order_acquire);
auto id_rd = circ::index_of(cur_rd);
auto id_wt = circ::index_of(cur_wt);
if (id_rd == id_wt) {
auto* el = elems + id_wt;
auto cac_ct = el->f_ct_.load(std::memory_order_acquire);
if ((~cac_ct) != cur_wt) {
return false; // empty
}
if (el->f_ct_.compare_exchange_weak(cac_ct, 0, std::memory_order_relaxed)) {
wt_.store(cur_wt + 1, std::memory_order_release);
}
k = 0;
}
else {
std::memcpy(buff, &(elems[circ::index_of(cur_rd)].data_), sizeof(buff));
if (rd_.compare_exchange_weak(cur_rd, cur_rd + 1, std::memory_order_release)) {
std::forward<F>(f)(buff);
return true;
}
ipc::yield(k);
}
}
}
};
template <>
struct prod_cons_impl<wr<relat::single, relat::multi, trans::broadcast>> {
using rc_t = std::size_t;
template <std::size_t DataSize, std::size_t AlignSize>
struct elem_t {
std::aligned_storage_t<DataSize, AlignSize> data_ {};
std::atomic<rc_t> rc_ { 0 }; // read-counter
};
alignas(circ::cache_line_size) std::atomic<circ::u2_t> wt_; // write index
circ::u2_t cursor() const noexcept {
return wt_.load(std::memory_order_acquire);
}
template <typename W, typename F, typename E>
bool push(W* wrapper, F&& f, E* elems) {
auto cc = wrapper->conn_count(std::memory_order_relaxed);
if (cc == 0) return false; // no reader
auto* el = elems + circ::index_of(wt_.load(std::memory_order_acquire));
// check all consumers have finished reading this element
rc_t expected = 0;
if (!el->rc_.compare_exchange_strong(
expected, static_cast<rc_t>(cc), std::memory_order_acq_rel)) {
return false; // full
}
std::forward<F>(f)(&(el->data_));
wt_.fetch_add(1, std::memory_order_release);
return true;
}
template <typename W, typename F, typename E>
bool force_push(W* wrapper, F&& f, E* elems) {
auto cc = wrapper->conn_count(std::memory_order_relaxed);
if (cc == 0) return false; // no reader
cc = wrapper->disconnect() - 1; // disconnect a reader
if (cc == 0) return false; // no reader
auto* el = elems + circ::index_of(wt_.load(std::memory_order_acquire));
// reset reading flag
el->rc_.store(static_cast<rc_t>(cc), std::memory_order_relaxed);
std::forward<F>(f)(&(el->data_));
wt_.fetch_add(1, std::memory_order_release);
return true;
}
template <typename W, typename F, typename E>
bool pop(W* /*wrapper*/, circ::u2_t& cur, F&& f, E* elems) {
if (cur == cursor()) return false; // acquire
auto* el = elems + circ::index_of(cur++);
std::forward<F>(f)(&(el->data_));
for (unsigned k = 0;;) {
rc_t cur_rc = el->rc_.load(std::memory_order_acquire);
if (cur_rc == 0) {
return true;
}
if (el->rc_.compare_exchange_weak(
cur_rc, cur_rc - 1, std::memory_order_release)) {
return true;
}
ipc::yield(k);
}
}
};
template <>
struct prod_cons_impl<wr<relat::multi , relat::multi, trans::broadcast>> {
using rc_t = std::uint64_t;
using flag_t = std::uint64_t;
enum : rc_t {
rc_mask = 0x00000000ffffffffull,
rc_incr = 0x0000000100000000ull
};
template <std::size_t DataSize, std::size_t AlignSize>
struct elem_t {
std::aligned_storage_t<DataSize, AlignSize> data_ {};
std::atomic<rc_t > rc_ { 0 }; // read-counter
std::atomic<flag_t> f_ct_ { 0 }; // commit flag
};
alignas(circ::cache_line_size) std::atomic<circ::u2_t> ct_; // commit index
circ::u2_t cursor() const noexcept {
return ct_.load(std::memory_order_acquire);
}
template <typename W, typename F, typename E>
bool push(W* wrapper, F&& f, E* elems) {
E* el;
circ::u2_t cur_ct;
for (unsigned k = 0;;) {
auto cc = wrapper->conn_count(std::memory_order_relaxed);
if (cc == 0) {
return false; // no reader
}
el = elems + circ::index_of(cur_ct = ct_.load(std::memory_order_relaxed));
auto cur_rc = el->rc_.load(std::memory_order_acquire);
if (cur_rc & rc_mask) {
return false; // full
}
auto cur_fl = el->f_ct_.load(std::memory_order_acquire);
if ((cur_fl != cur_ct) && cur_fl) {
return false; // full
}
// (cur_rc & rc_mask) should == 0 here
if (el->rc_.compare_exchange_weak(
cur_rc, static_cast<rc_t>(cc) | ((cur_rc & ~rc_mask) + rc_incr), std::memory_order_release)) {
break;
}
ipc::yield(k);
}
// only one thread/process would touch here at one time
ct_.store(cur_ct + 1, std::memory_order_release);
std::forward<F>(f)(&(el->data_));
// set flag & try update wt
el->f_ct_.store(~static_cast<flag_t>(cur_ct), std::memory_order_release);
return true;
}
template <typename W, typename F, typename E>
bool force_push(W* wrapper, F&& f, E* elems) {
E* el;
circ::u2_t cur_ct;
auto cc = wrapper->conn_count(std::memory_order_relaxed);
if (cc == 0) return false; // no reader
wrapper->disconnect(); // disconnect a reader
for (unsigned k = 0;;) {
cc = wrapper->conn_count(std::memory_order_relaxed);
if (cc == 0) return false; // no reader
el = elems + circ::index_of(cur_ct = ct_.load(std::memory_order_relaxed));
auto cur_rc = el->rc_.load(std::memory_order_acquire);
el->rc_.store(static_cast<rc_t>(cc) | ((cur_rc & ~rc_mask) + rc_incr), std::memory_order_relaxed);
if (ct_.compare_exchange_weak(cur_ct, cur_ct + 1, std::memory_order_release)) {
break;
}
ipc::yield(k);
}
std::forward<F>(f)(&(el->data_));
// set flag & try update wt
el->f_ct_.store(~static_cast<flag_t>(cur_ct), std::memory_order_release);
return true;
}
template <typename W, typename F, typename E, std::size_t N>
bool pop(W* /*wrapper*/, circ::u2_t& cur, F&& f, E(& elems)[N]) {
auto* el = elems + circ::index_of(cur);
auto cur_fl = el->f_ct_.load(std::memory_order_acquire);
if (cur_fl != ~static_cast<flag_t>(cur)) {
return false; // empty
}
++cur;
std::forward<F>(f)(&(el->data_));
for (unsigned k = 0;;) {
auto cur_rc = el->rc_.load(std::memory_order_acquire);
switch (cur_rc & rc_mask) {
case 0:
el->f_ct_.store(cur + N - 1, std::memory_order_release);
return true;
case 1:
el->f_ct_.store(cur + N - 1, std::memory_order_release);
[[fallthrough]];
default:
if (el->rc_.compare_exchange_weak(
cur_rc, cur_rc + rc_incr - 1, std::memory_order_release)) {
return true;
}
break;
}
ipc::yield(k);
}
}
};
} // namespace ipc