Merge branch 'iocp_option'

8 files changed, 103 insertions, 9 deletions

diff --git a/src/common/compat.c b/src/common/compat.c
index 20394b4c5..b7f4f17ca 100644
--- a/src/common/compat.c
+++ b/src/common/compat.c
@@ -1898,6 +1898,52 @@ spawn_exit(void)
 #endif
 }
 
+/** Implementation logic for compute_num_cpus(). */
+static int
+compute_num_cpus_impl(void)
+{
+#ifdef MS_WINDOWS
+  SYSTEM_INFO info;
+  memset(&info, 0, sizeof(info));
+  GetSystemInfo(&info);
+  if (info.dwNumberOfProcessors >= 1 && info.dwNumberOfProcessors < INT_MAX)
+    return (int)info.dwNumberOfProcessors;
+  else
+    return -1;
+#elif defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_CONF)
+  long cpus = sysconf(_SC_NPROCESSORS_CONF);
+  if (cpus >= 1 && cpus < INT_MAX)
+    return (int)cpus;
+  else
+    return -1;
+#else
+  return -1;
+#endif
+}
+
+#define MAX_DETECTABLE_CPUS 16
+
+/** Return how many CPUs we are running with.  We assume that nobody is
+ * using hot-swappable CPUs, so we don't recompute this after the first
+ * time.  Return -1 if we don't know how to tell the number of CPUs on this
+ * system.
+ */
+int
+compute_num_cpus(void)
+{
+  static int num_cpus = -2;
+  if (num_cpus == -2) {
+    num_cpus = compute_num_cpus_impl();
+    tor_assert(num_cpus != -2);
+    if (num_cpus > MAX_DETECTABLE_CPUS)
+      log_notice(LD_GENERAL, "Wow!  I detected that you have %d CPUs. I "
+                 "will not autodetect any more than %d, though.  If you "
+                 "want to configure more, set NumCPUs in your torrc",
+                 num_cpus, MAX_DETECTABLE_CPUS);
+  }
+  return num_cpus;
+}
+
 /** Set *timeval to the current time of day.  On error, log and terminate.
  * (Same as gettimeofday(timeval,NULL), but never returns -1.)
  */
diff --git a/src/common/compat.h b/src/common/compat.h
index 7d59501e2..5b6cfc40b 100644
--- a/src/common/compat.h
+++ b/src/common/compat.h
@@ -522,6 +522,8 @@ void spawn_exit(void) ATTR_NORETURN;
 #undef TOR_IS_MULTITHREADED
 #endif
 
+int compute_num_cpus(void);
+
 /* Because we use threads instead of processes on most platforms (Windows,
  * Linux, etc), we need locking for them.  On platforms with poor thread
  * support or broken gethostbyname_r, these functions are no-ops. */
diff --git a/src/common/compat_libevent.c b/src/common/compat_libevent.c
index bbab06e8d..6afd3c1d2 100644
--- a/src/common/compat_libevent.c
+++ b/src/common/compat_libevent.c
@@ -159,7 +159,7 @@ struct event_base *the_event_base = NULL;
 
 /** Initialize the Libevent library and set up the event base. */
 void
-tor_libevent_initialize(void)
+tor_libevent_initialize(tor_libevent_cfg *torcfg)
 {
   tor_assert(the_event_base == NULL);
 
@@ -171,7 +171,21 @@ tor_libevent_initialize(void)
 #endif
 
 #ifdef HAVE_EVENT2_EVENT_H
-  the_event_base = event_base_new();
+  {
+    struct event_config *cfg = event_config_new();
+
+#if defined(MS_WINDOWS) && defined(USE_BUFFEREVENTS)
+    if (! torcfg->disable_iocp)
+      event_config_set_flag(cfg, EVENT_BASE_FLAG_STARTUP_IOCP);
+#endif
+
+#if defined(LIBEVENT_VERSION_NUMBER) && LIBEVENT_VERSION_NUMBER >= V(2,0,7)
+    if (torcfg->num_cpus > 0)
+      event_config_set_num_cpus_hint(cfg, torcfg->num_cpus);
+#endif
+
+    the_event_base = event_base_new_with_config(cfg);
+  }
 #else
   the_event_base = event_init();
 #endif
diff --git a/src/common/compat_libevent.h b/src/common/compat_libevent.h
index f483d6ee6..ecf25806d 100644
--- a/src/common/compat_libevent.h
+++ b/src/common/compat_libevent.h
@@ -56,7 +56,12 @@ struct timeval;
 int tor_event_base_loopexit(struct event_base *base, struct timeval *tv);
 #endif
 
-void tor_libevent_initialize(void);
+typedef struct tor_libevent_cfg {
+  int disable_iocp;
+  int num_cpus;
+} tor_libevent_cfg;
+
+void tor_libevent_initialize(tor_libevent_cfg *cfg);
 struct event_base *tor_libevent_get_base(void);
 const char *tor_libevent_get_method(void);
 void tor_check_libevent_version(const char *m, int server,
diff --git a/src/or/config.c b/src/or/config.c
index 6d8addeb2..23cad9268 100644
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -224,6 +224,7 @@ static config_var_t _option_vars[] = {
   V(DirReqStatistics,            BOOL,     "0"),
   VAR("DirServer",               LINELIST, DirServers, NULL),
   V(DisableAllSwap,              BOOL,     "0"),
+  V(DisableIOCP,                 BOOL,     "1"),
   V(DNSPort,                     UINT,     "0"),
   V(DNSListenAddress,            LINELIST, NULL),
   V(DownloadExtraInfo,           BOOL,     "0"),
@@ -306,7 +307,7 @@ static config_var_t _option_vars[] = {
   V(WarnUnsafeSocks,              BOOL,     "1"),
   V(NoPublish,                   BOOL,     "0"),
   VAR("NodeFamily",              LINELIST, NodeFamilies,         NULL),
-  V(NumCpus,                     UINT,     "1"),
+  V(NumCpus,                     UINT,     "0"),
   V(NumEntryGuards,              UINT,     "3"),
   V(ORListenAddress,             LINELIST, NULL),
   V(ORPort,                      UINT,     "0"),
@@ -554,7 +555,7 @@ static int is_listening_on_low_port(uint16_t port_option,
 
 static uint64_t config_parse_memunit(const char *s, int *ok);
 static int config_parse_interval(const char *s, int *ok);
-static void init_libevent(void);
+static void init_libevent(const or_options_t *options);
 static int opt_streq(const char *s1, const char *s2);
 
 /** Magic value for or_options_t. */
@@ -955,7 +956,7 @@ options_act_reversible(or_options_t *old_options, char **msg)
     /* Set up libevent.  (We need to do this before we can register the
      * listeners as listeners.) */
     if (running_tor && !libevent_initialized) {
-      init_libevent();
+      init_libevent(options);
       libevent_initialized = 1;
     }
 
@@ -4891,13 +4892,29 @@ config_parse_interval(const char *s, int *ok)
   return (int)r;
 }
 
+/** Return the number of cpus configured in <b>options</b>.  If we are
+ * told to auto-detect the number of cpus, return the auto-detected number. */
+int
+get_num_cpus(const or_options_t *options)
+{
+  if (options->NumCpus == 0) {
+    int n = compute_num_cpus();
+    return (n >= 1) ? n : 1;
+  } else {
+    return options->NumCpus;
+  }
+}
+
 /**
  * Initialize the libevent library.
  */
 static void
-init_libevent(void)
+init_libevent(const or_options_t *options)
 {
   const char *badness=NULL;
+  tor_libevent_cfg cfg;
+
+  tor_assert(options);
 
   configure_libevent_logging();
   /* If the kernel complains that some method (say, epoll) doesn't
@@ -4907,7 +4924,11 @@ init_libevent(void)
 
   tor_check_libevent_header_compatibility();
 
-  tor_libevent_initialize();
+  memset(&cfg, 0, sizeof(cfg));
+  cfg.disable_iocp = options->DisableIOCP;
+  cfg.num_cpus = get_num_cpus(options);
+
+  tor_libevent_initialize(&cfg);
 
   suppress_libevent_log_msg(NULL);
 
diff --git a/src/or/config.h b/src/or/config.h
index 7a4ba5c60..bd5827b4e 100644
--- a/src/or/config.h
+++ b/src/or/config.h
@@ -57,6 +57,8 @@ char *options_get_datadir_fname2_suffix(or_options_t *options,
 #define get_datadir_fname_suffix(sub1, suffix) \
   get_datadir_fname2_suffix((sub1), NULL, (suffix))
 
+int get_num_cpus(const or_options_t *options);
+
 or_state_t *get_or_state(void);
 int or_state_save(time_t now);
 
diff --git a/src/or/cpuworker.c b/src/or/cpuworker.c
index e5b2c7102..cfe9f3af9 100644
--- a/src/or/cpuworker.c
+++ b/src/or/cpuworker.c
@@ -366,7 +366,7 @@ spawn_cpuworker(void)
 static void
 spawn_enough_cpuworkers(void)
 {
-  int num_cpuworkers_needed = get_options()->NumCpus;
+  int num_cpuworkers_needed = get_num_cpus(get_options());
 
   if (num_cpuworkers_needed < MIN_CPUWORKERS)
     num_cpuworkers_needed = MIN_CPUWORKERS;
diff --git a/src/or/or.h b/src/or/or.h
index 4741cc341..d2a7714db 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -2892,6 +2892,10 @@ typedef struct {
    */
   double CircuitPriorityHalflife;
 
+  /** If true, do not enable IOCP on windows with bufferevents, even if
+   * we think we could. */
+  int DisableIOCP;
+
 } or_options_t;
 
 /** Persistent state for an onion router, as saved to disk. */