Use a separate thread for epoll

Simplest, but absolutely inefficient, way to test openonload epoll

Makefile

@@ -18,7 +18,7 @@ OSD_OBJS := osd.o osd_secondary.o msgr_receive.o msgr_send.o osd_peering.o osd_f
 	osd_primary.o osd_primary_subops.o etcd_state_client.o messenger.o osd_cluster.o http_client.o pg_states.o \
 	osd_rmw.o json11.o base64.o timerfd_manager.o
 osd: ./libblockstore.so osd_main.cpp osd.h osd_ops.h $(OSD_OBJS)
-	g++ $(CXXFLAGS) -o $@ osd_main.cpp $(OSD_OBJS) ./libblockstore.so -ltcmalloc_minimal -luring
+	g++ $(CXXFLAGS) -o $@ osd_main.cpp $(OSD_OBJS) ./libblockstore.so -ltcmalloc_minimal -luring -lpthread
 
 stub_osd: stub_osd.o rw_blocking.o
 	g++ $(CXXFLAGS) -o $@ stub_osd.o rw_blocking.o -ltcmalloc_minimal
@@ -87,7 +87,7 @@ dump_journal.o: dump_journal.cpp allocator.h blockstore.h blockstore_flush.h blo
 	g++ $(CXXFLAGS) -c -o $@ $<
 epoll_manager.o: epoll_manager.cpp epoll_manager.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
-etcd_state_client.o: etcd_state_client.cpp base64.h etcd_state_client.h http_client.h json11/json11.hpp object_id.h osd_id.h osd_ops.h pg_states.h timerfd_manager.h
+etcd_state_client.o: etcd_state_client.cpp base64.h etcd_state_client.h http_client.h json11/json11.hpp object_id.h osd_id.h osd_ops.h pg_states.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 fio_cluster.o: fio_cluster.cpp cluster_client.h epoll_manager.h etcd_state_client.h fio/fio.h fio/optgroup.h http_client.h json11/json11.hpp messenger.h object_id.h osd_id.h osd_ops.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
@@ -95,7 +95,7 @@ fio_engine.o: fio_engine.cpp blockstore.h fio/fio.h fio/optgroup.h json11/json11
 	g++ $(CXXFLAGS) -c -o $@ $<
 fio_sec_osd.o: fio_sec_osd.cpp fio/fio.h fio/optgroup.h object_id.h osd_id.h osd_ops.h rw_blocking.h
 	g++ $(CXXFLAGS) -c -o $@ $<
-http_client.o: http_client.cpp http_client.h json11/json11.hpp timerfd_manager.h
+http_client.o: http_client.cpp http_client.h json11/json11.hpp ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
 messenger.o: messenger.cpp json11/json11.hpp messenger.h object_id.h osd_id.h osd_ops.h ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<
@@ -149,5 +149,5 @@ test_blockstore.o: test_blockstore.cpp blockstore.h object_id.h ringloop.h timer
 	g++ $(CXXFLAGS) -c -o $@ $<
 timerfd_interval.o: timerfd_interval.cpp ringloop.h timerfd_interval.h
 	g++ $(CXXFLAGS) -c -o $@ $<
-timerfd_manager.o: timerfd_manager.cpp timerfd_manager.h
+timerfd_manager.o: timerfd_manager.cpp ringloop.h timerfd_manager.h
 	g++ $(CXXFLAGS) -c -o $@ $<

blockstore_flush.cpp

@@ -33,12 +33,6 @@ journal_flusher_co::journal_flusher_co()
             );
         }
         wait_count--;
-        if (!wait_count)
-        {
-            timespec now;
-            clock_gettime(CLOCK_REALTIME, &now);
-            printf("finished %s %d %ld.%06ld\n", __FILE__, __LINE__, now.tv_sec, now.tv_nsec/1000);
-        }
     };
     simple_callback_w = [this](ring_data_t* data)
     {
@@ -51,12 +45,6 @@ journal_flusher_co::journal_flusher_co()
             );
         }
         wait_count--;
-        if (!wait_count)
-        {
-            timespec now;
-            clock_gettime(CLOCK_REALTIME, &now);
-            printf("finished %s %d %ld.%06ld\n", __FILE__, __LINE__, now.tv_sec, now.tv_nsec/1000);
-        }
     };
 }
 
@@ -134,11 +122,6 @@ void journal_flusher_t::release_trim()
 
 #define await_sqe(label) \
     resume_##label:\
-        {\
-            timespec now;\
-            clock_gettime(CLOCK_REALTIME, &now);\
-            printf("get_sqe %s %d %ld.%06ld\n", __FILE__, __LINE__, now.tv_sec, now.tv_nsec/1000);\
-        }\
         sqe = bs->get_sqe();\
         if (!sqe)\
         {\

blockstore_impl.h

@@ -62,11 +62,6 @@
     struct ring_data_t *data = ((ring_data_t*)sqe->user_data)
 
 #define BS_SUBMIT_GET_ONLY_SQE(sqe) \
-        {\
-            timespec now;\
-            clock_gettime(CLOCK_REALTIME, &now);\
-            printf("get_sqe %s %d %ld.%06ld\n", __FILE__, __LINE__, now.tv_sec, now.tv_nsec/1000);\
-        }\
     struct io_uring_sqe *sqe = get_sqe();\
     if (!sqe)\
     {\
@@ -76,11 +71,6 @@
     }
 
 #define BS_SUBMIT_GET_SQE_DECL(sqe) \
-        {\
-            timespec now;\
-            clock_gettime(CLOCK_REALTIME, &now);\
-            printf("get_sqe %s %d %ld.%06ld\n", __FILE__, __LINE__, now.tv_sec, now.tv_nsec/1000);\
-        }\
     sqe = get_sqe();\
     if (!sqe)\
     {\

blockstore_stable.cpp

@@ -147,11 +147,6 @@ resume_2:
 resume_3:
     if (!disable_journal_fsync)
     {
-        {
-            timespec now;
-            clock_gettime(CLOCK_REALTIME, &now);
-            printf("get_sqe %s %d %ld.%06ld\n", __FILE__, __LINE__, now.tv_sec, now.tv_nsec/1000);
-        }
         io_uring_sqe *sqe = get_sqe();
         if (!sqe)
         {
@@ -242,11 +237,6 @@ void blockstore_impl_t::handle_stable_event(ring_data_t *data, blockstore_op_t *
     PRIV(op)->pending_ops--;
     if (PRIV(op)->pending_ops == 0)
     {
-        {
-            timespec now;
-            clock_gettime(CLOCK_REALTIME, &now);
-            printf("finished %s %d %ld.%06ld\n", __FILE__, __LINE__, now.tv_sec, now.tv_nsec/1000);
-        }
         PRIV(op)->op_state++;
         if (!continue_stable(op))
         {

blockstore_write.cpp

@@ -302,11 +302,6 @@ int blockstore_impl_t::continue_write(blockstore_op_t *op)
         return 1;
 resume_2:
     // Only for the immediate_commit mode: prepare and submit big_write journal entry
-        {
-            timespec now;
-            clock_gettime(CLOCK_REALTIME, &now);
-            printf("get_sqe %s %d %ld.%06ld\n", __FILE__, __LINE__, now.tv_sec, now.tv_nsec/1000);
-        }
     sqe = get_sqe();
     if (!sqe)
     {
@@ -338,11 +333,6 @@ resume_2:
     return 1;
 resume_4:
     // Switch object state
-        {
-            timespec now;
-            clock_gettime(CLOCK_REALTIME, &now);
-            printf("write_done %s %d %ld.%06ld\n", __FILE__, __LINE__, now.tv_sec, now.tv_nsec/1000);
-        }
 #ifdef BLOCKSTORE_DEBUG
     printf("Ack write %lu:%lu v%lu = %d\n", op->oid.inode, op->oid.stripe, op->version, dirty_it->second.state);
 #endif

epoll_manager.cpp

@@ -57,11 +57,6 @@ void epoll_manager_t::set_fd_handler(int fd, std::function<void(int, int)> handl
 
 void epoll_manager_t::handle_epoll_events()
 {
-    {
-        timespec now;
-        clock_gettime(CLOCK_REALTIME, &now);
-        printf("epoll %s %d %ld.%06ld\n", __FILE__, __LINE__, now.tv_sec, now.tv_nsec/1000);
-    }
     io_uring_sqe *sqe = ringloop->get_sqe();
     if (!sqe)
     {

msgr_receive.cpp

@@ -24,11 +24,6 @@ void osd_messenger_t::read_requests()
         {
             result = -errno;
         }
-        {
-            timespec now;
-            clock_gettime(CLOCK_REALTIME, &now);
-            printf("recvmsg done %s %d %ld.%06ld\n", __FILE__, __LINE__, now.tv_sec, now.tv_nsec/1000);
-        }
         handle_read(result, peer_fd);
     }
 }

msgr_send.cpp

@@ -81,11 +81,6 @@ bool osd_messenger_t::try_send(osd_client_t & cl)
     int result = sendmsg(peer_fd, &cl.write_msg, MSG_NOSIGNAL);
     if (result < 0)
         result = -errno;
-    {
-        timespec now;
-        clock_gettime(CLOCK_REALTIME, &now);
-        printf("sendmsg done %s %d %ld.%06ld\n", __FILE__, __LINE__, now.tv_sec, now.tv_nsec/1000);
-    }
     handle_send(result, peer_fd);
     return true;
 }

osd.cpp

@@ -1,5 +1,6 @@
 #include <sys/socket.h>
 #include <sys/epoll.h>
+#include <sys/eventfd.h>
 #include <sys/poll.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
@@ -43,8 +44,14 @@ osd_t::osd_t(blockstore_config_t & config, blockstore_t *bs, ring_loop_t *ringlo
     {
         throw std::runtime_error(std::string("epoll_create: ") + strerror(errno));
     }
+    event_fd = eventfd(0, EFD_NONBLOCK);
+    if (event_fd < 0)
+    {
+        throw std::runtime_error(std::string("eventfd: ") + strerror(errno));
+    }
 
-    this->tfd = new timerfd_manager_t([this](int fd, std::function<void(int, int)> handler) { set_fd_handler(fd, handler); });
+    this->tfd = new timerfd_manager_t(ringloop);
+    this->tfd->set_fd_handler = [this](int fd, std::function<void(int, int)> handler) { set_fd_handler(fd, handler); };
     this->tfd->set_timer(print_stats_interval*1000, true, [this](int timer_id)
     {
         print_stats();
@@ -59,17 +66,40 @@ osd_t::osd_t(blockstore_config_t & config, blockstore_t *bs, ring_loop_t *ringlo
 
     consumer.loop = [this]() { loop(); };
     ringloop->register_consumer(&consumer);
+    epoll_thread = new std::thread([this]()
+    {
+        int nfds;
+        epoll_event events[MAX_EPOLL_EVENTS];
+        while (1)
+        {
+            nfds = epoll_wait(epoll_fd, events, MAX_EPOLL_EVENTS, -1);
+            {
+                std::lock_guard<std::mutex> guard(epoll_mutex);
+                for (int i = 0; i < nfds; i++)
+                {
+                    int fd = events[i].data.fd;
+                    int ev = events[i].events;
+                    epoll_ready[fd] |= ev;
+                }
+                uint64_t n = 1;
+                write(event_fd, &n, 8);
+            }
+        }
+    });
 }
 
 osd_t::~osd_t()
 {
+    close(epoll_fd);
+    epoll_thread->join();
+    delete epoll_thread;
     if (tfd)
     {
         delete tfd;
         tfd = NULL;
     }
     ringloop->unregister_consumer(&consumer);
-    close(epoll_fd);
+    close(event_fd);
     close(listen_fd);
 }
 
@@ -188,8 +218,13 @@ void osd_t::bind_socket()
     {
         close(listen_fd);
         close(epoll_fd);
-        throw std::runtime_error(std::string("epoll_ctl: ") + strerror(errno));
+        throw std::runtime_error(std::string("epoll_ctl (add listen_fd): ") + strerror(errno));
     }
+
+    epoll_handlers[listen_fd] = [this](int peer_fd, int epoll_events)
+    {
+        c_cli.accept_connections(listen_fd);
+    };
 }
 
 bool osd_t::shutdown()
@@ -204,10 +239,23 @@ bool osd_t::shutdown()
 
 void osd_t::loop()
 {
-    if (!wait_state)
+    std::map<int,int> cur_epoll;
     {
-        handle_epoll_events();
+        std::lock_guard<std::mutex> guard(epoll_mutex);
-        wait_state = 1;
+        cur_epoll.swap(epoll_ready);
+    }
+    for (auto p: cur_epoll)
+    {
+        auto cb_it = epoll_handlers.find(p.first);
+        if (cb_it != epoll_handlers.end())
+        {
+            cb_it->second(p.first, p.second);
+        }
+    }
+    if (!(wait_state & 2))
+    {
+        handle_eventfd();
+        wait_state = wait_state | 2;
     }
     handle_peers();
     c_cli.read_requests();
@@ -225,7 +273,7 @@ void osd_t::set_fd_handler(int fd, std::function<void(int, int)> handler)
         ev.events = EPOLLOUT | EPOLLIN | EPOLLRDHUP | EPOLLET;
         if (epoll_ctl(epoll_fd, exists ? EPOLL_CTL_MOD : EPOLL_CTL_ADD, fd, &ev) < 0)
         {
-            throw std::runtime_error(std::string("epoll_ctl: ") + strerror(errno));
+            throw std::runtime_error(std::string(exists ? "epoll_ctl (mod fd): " : "epoll_ctl (add fd): ") + strerror(errno));
         }
         epoll_handlers[fd] = handler;
     }
@@ -233,54 +281,36 @@ void osd_t::set_fd_handler(int fd, std::function<void(int, int)> handler)
     {
         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, fd, NULL) < 0 && errno != ENOENT)
         {
-            throw std::runtime_error(std::string("epoll_ctl: ") + strerror(errno));
+            throw std::runtime_error(std::string("epoll_ctl (remove fd): ") + strerror(errno));
         }
         epoll_handlers.erase(fd);
     }
 }
 
-void osd_t::handle_epoll_events()
+void osd_t::handle_eventfd()
 {
-    {
-        timespec now;
-        clock_gettime(CLOCK_REALTIME, &now);
-        printf("epoll %s %d %ld.%06ld\n", __FILE__, __LINE__, now.tv_sec, now.tv_nsec/1000);
-    }
     io_uring_sqe *sqe = ringloop->get_sqe();
     if (!sqe)
     {
-        throw std::runtime_error("can't get SQE, will fall out of sync with EPOLLET");
+        throw std::runtime_error("can't get SQE, will fall out of sync with eventfd");
     }
     ring_data_t *data = ((ring_data_t*)sqe->user_data);
-    my_uring_prep_poll_add(sqe, epoll_fd, POLLIN);
+    my_uring_prep_poll_add(sqe, event_fd, POLLIN);
     data->callback = [this](ring_data_t *data)
     {
         if (data->res < 0)
         {
             throw std::runtime_error(std::string("epoll failed: ") + strerror(-data->res));
         }
-        handle_epoll_events();
+        handle_eventfd();
     };
     ringloop->submit();
-    int nfds;
+    uint64_t n = 0;
-    epoll_event events[MAX_EPOLL_EVENTS];
+    size_t res = read(event_fd, &n, 8);
-restart:
+    if (res == 8)
-    nfds = epoll_wait(epoll_fd, events, MAX_EPOLL_EVENTS, 0);
-    for (int i = 0; i < nfds; i++)
     {
-        if (events[i].data.fd == listen_fd)
+        // No need to do anything, the loop has already woken up
-        {
+        ringloop->wakeup();
-            c_cli.accept_connections(listen_fd);
-        }
-        else
-        {
-            auto & cb = epoll_handlers[events[i].data.fd];
-            cb(events[i].data.fd, events[i].events);
-        }
-    }
-    if (nfds == MAX_EPOLL_EVENTS)
-    {
-        goto restart;
     }
 }
 

osd.h

@@ -12,6 +12,8 @@
 
 #include <set>
 #include <deque>
+#include <mutex>
+#include <thread>
 
 #include "blockstore.h"
 #include "ringloop.h"
@@ -114,6 +116,10 @@ class osd_t
 
     int wait_state = 0;
     int epoll_fd = 0;
+    int event_fd = 0;
+    std::thread *epoll_thread = NULL;
+    std::mutex epoll_mutex;
+    std::map<int, int> epoll_ready;
     int listening_port = 0;
     int listen_fd = 0;
     ring_consumer_t consumer;
@@ -150,7 +156,7 @@ class osd_t
     // event loop, socket read/write
     void loop();
     void set_fd_handler(int fd, std::function<void(int, int)> handler);
-    void handle_epoll_events();
+    void handle_eventfd();
 
     // peer handling (primary OSD logic)
     void parse_test_peer(std::string peer);

osd_primary.cpp

@@ -198,7 +198,6 @@ void osd_t::continue_primary_write(osd_op_t *cur_op)
     else if (op_data->st == 8) goto resume_8;
     else if (op_data->st == 9) goto resume_9;
     assert(op_data->st == 0);
-    printf("primary_write\n");
     if (!check_write_queue(cur_op, pg))
     {
         return;
@@ -390,7 +389,6 @@ void osd_t::continue_primary_sync(osd_op_t *cur_op)
     else if (op_data->st == 5) goto resume_5;
     else if (op_data->st == 6) goto resume_6;
     assert(op_data->st == 0);
-    printf("primary_sync\n");
     if (syncs_in_progress.size() > 0)
     {
         // Wait for previous syncs, if any

ringloop.h

@@ -4,8 +4,6 @@
 #define _LARGEFILE64_SOURCE
 #endif
 
-#include <stdio.h>
-#include <time.h>
 #include <string.h>
 #include <assert.h>
 #include <liburing.h>
@@ -160,13 +158,7 @@ public:
     }
     inline int submit()
     {
-        int r = io_uring_submit(&ring);
+        return io_uring_submit(&ring);
-        {
-            timespec now;
-            clock_gettime(CLOCK_REALTIME, &now);
-            printf("submit %s %d %ld.%06ld\n", __FILE__, __LINE__, now.tv_sec, now.tv_nsec/1000);
-        }
-        return r;
     }
     inline int wait()
     {

timerfd_manager.cpp

@@ -1,29 +1,24 @@
 #include <sys/timerfd.h>
 #include <sys/poll.h>
-#include <sys/epoll.h>
 #include <unistd.h>
-#include <errno.h>
-#include <string.h>
 #include "timerfd_manager.h"
 
-timerfd_manager_t::timerfd_manager_t(std::function<void(int, std::function<void(int, int)>)> set_fd_handler)
+timerfd_manager_t::timerfd_manager_t(ring_loop_t *ringloop)
 {
-    this->set_fd_handler = set_fd_handler;
     wait_state = 0;
     timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK);
     if (timerfd < 0)
     {
         throw std::runtime_error(std::string("timerfd_create: ") + strerror(errno));
     }
-    set_fd_handler(timerfd, [this](int fd, int events)
+    consumer.loop = [this]() { loop(); };
-    {
+    ringloop->register_consumer(&consumer);
-        handle_readable();
+    this->ringloop = ringloop;
-    });
 }
 
 timerfd_manager_t::~timerfd_manager_t()
 {
-    set_fd_handler(timerfd, NULL);
+    ringloop->unregister_consumer(&consumer);
     close(timerfd);
 }
 
@@ -53,6 +48,7 @@ int timerfd_manager_t::set_timer(uint64_t millis, bool repeat, std::function<voi
     });
     inc_timer(timers[timers.size()-1]);
     set_nearest();
+    set_wait();
     return timer_id;
 }
 
@@ -73,6 +69,7 @@ void timerfd_manager_t::clear_timer(int timer_id)
                 nearest--;
             }
             set_nearest();
+            set_wait();
             break;
         }
     }
@@ -157,3 +154,36 @@ void timerfd_manager_t::trigger_nearest()
     cb(nearest_id);
     nearest = -1;
 }
+
+void timerfd_manager_t::loop()
+{
+    if (!(wait_state & 1) && timers.size())
+    {
+        set_nearest();
+    }
+    set_wait();
+}
+
+void timerfd_manager_t::set_wait()
+{
+    if ((wait_state & 3) == 1)
+    {
+        io_uring_sqe *sqe = ringloop->get_sqe();
+        if (!sqe)
+        {
+            return;
+        }
+        ring_data_t *data = ((ring_data_t*)sqe->user_data);
+        my_uring_prep_poll_add(sqe, timerfd, POLLIN);
+        data->callback = [this](ring_data_t *data)
+        {
+            if (data->res < 0)
+            {
+                throw std::runtime_error(std::string("waiting for timer failed: ") + strerror(-data->res));
+            }
+            handle_readable();
+            set_wait();
+        };
+        wait_state = 3;
+    }
+}

timerfd_manager.h

@@ -1,8 +1,7 @@
 #pragma once
 
 #include <time.h>
-#include <vector>
+#include "ringloop.h"
-#include <functional>
 
 struct timerfd_timer_t
 {
@@ -20,15 +19,20 @@ class timerfd_manager_t
     int nearest = -1;
     int id = 1;
     std::vector<timerfd_timer_t> timers;
+    ring_loop_t *ringloop;
+    ring_consumer_t consumer;
 
     void inc_timer(timerfd_timer_t & t);
     void set_nearest();
     void trigger_nearest();
     void handle_readable();
+    void set_wait();
+    void loop();
 public:
+    // FIXME shouldn't be here
     std::function<void(int, std::function<void(int, int)>)> set_fd_handler;
 
-    timerfd_manager_t(std::function<void(int, std::function<void(int, int)>)> set_fd_handler);
+    timerfd_manager_t(ring_loop_t *ringloop);
     ~timerfd_manager_t();
     int set_timer(uint64_t millis, bool repeat, std::function<void(int)> callback);
     void clear_timer(int timer_id);