initial support for dirty schedulers and dirty NIFs

Add initial support for dirty schedulers.

There are two types of dirty schedulers: CPU schedulers and I/O
schedulers. By default, there are as many dirty CPU schedulers as there are
normal schedulers and as many dirty CPU schedulers online as normal
schedulers online. There are 10 dirty I/O schedulers (similar to the choice
of 10 as the default for async threads).

By default, dirty schedulers are disabled and conditionally compiled
out. To enable them, you must pass --enable-dirty-schedulers to the
top-level configure script when building Erlang/OTP.

Current dirty scheduler support requires the emulator to be built with SMP
support. This restriction will be lifted in the future.

You can specify the number of dirty schedulers with the command-line
options +SDcpu (for dirty CPU schedulers) and +SDio (for dirty I/O
schedulers). The +SDcpu option is similar to the +S option in that it takes
two numbers separated by a colon: C1:C2, where C1 specifies the number of
dirty schedulers available and C2 specifies the number of dirty schedulers
online. The +SDPcpu option allows numbers of dirty CPU schedulers available
and dirty CPU schedulers online to be specified as percentages, similar to
the existing +SP option for normal schedulers. The number of dirty CPU
schedulers created and dirty CPU schedulers online may not exceed the
number of normal schedulers created and normal schedulers online,
respectively. The +SDio option takes only a single number specifying the
number of dirty I/O schedulers available and online. There is no support
yet for programmatically changing at run time the number of dirty CPU
schedulers online via erlang:system_flag/2. Also, changing the number of
normal schedulers online via erlang:system_flag(schedulers_online,
NewSchedulersOnline) should ensure that there are no more dirty CPU
schedulers than normal schedulers, but this is not yet implemented. You can
retrieve the number of dirty schedulers by passing dirty_cpu_schedulers,
dirty_cpu_schedulers_online, or dirty_io_schedulers to
erlang:system_info/1.

Currently only NIFs are able to access dirty scheduler
functionality. Neither drivers nor BIFs currently support dirty
schedulers. This restriction will be addressed in the future.

If dirty scheduler support is present in the runtime, the initial status
line Erlang prints before presenting its interactive prompt will include
the indicator "[ds:C1:C2:I]" where "ds" indicates "dirty schedulers", "C1"
indicates the number of dirty CPU schedulers available, "C2" indicates the
number of dirty CPU schedulers online, and "I" indicates the number of
dirty I/O schedulers.

Document The dirty NIF API in the erl_nif man page. The API closely follows
Rickard Green's presentation slides from his talk "Future Extensions to the
Native Interface", presented at the 2011 Erlang Factory held in the San
Francisco Bay Area. Rickard's slides are available online at
http://bit.ly/1m34UHB .

Document the new erl command-line options, the additions to
erlang:system_info/1, and also add the erlang:system_flag/2 dirty scheduler
documentation even though it's not yet implemented.

To determine whether the dirty NIF API is available, native code can check
to see whether the C preprocessor macro ERL_NIF_DIRTY_SCHEDULER_SUPPORT is
defined. To check if dirty schedulers are available at run time, native
code can call the boolean enif_have_dirty_schedulers() function, and Erlang
code can call erlang:system_info(dirty_cpu_schedulers), which raises
badarg if no dirty scheduler support is available.

Add a simple dirty NIF test to the emulator NIF suite.

1 files changed, 236 insertions, 68 deletions

diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index 19088fd913..c17256f466 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -484,98 +484,107 @@ void erts_usage(void)
 
     /*    erts_fprintf(stderr, "-# number  set the number of items to be used in traces etc\n"); */
 
-    erts_fprintf(stderr, "-a size     suggested stack size in kilo words for threads\n");
-    erts_fprintf(stderr, "            in the async-thread pool, valid range is [%d-%d]\n",
+    erts_fprintf(stderr, "-a size        suggested stack size in kilo words for threads\n");
+    erts_fprintf(stderr, "               in the async-thread pool, valid range is [%d-%d]\n",
 		 ERTS_ASYNC_THREAD_MIN_STACK_SIZE,
 		 ERTS_ASYNC_THREAD_MAX_STACK_SIZE);
-    erts_fprintf(stderr, "-A number   set number of threads in async thread pool,\n");
-    erts_fprintf(stderr, "            valid range is [0-%d]\n",
+    erts_fprintf(stderr, "-A number      set number of threads in async thread pool,\n");
+    erts_fprintf(stderr, "               valid range is [0-%d]\n",
 		 ERTS_MAX_NO_OF_ASYNC_THREADS);
 
-    erts_fprintf(stderr, "-B[c|d|i]   c to have Ctrl-c interrupt the Erlang shell,\n");
-    erts_fprintf(stderr, "            d (or no extra option) to disable the break\n");
-    erts_fprintf(stderr, "            handler, i to ignore break signals\n");
+    erts_fprintf(stderr, "-B[c|d|i]      c to have Ctrl-c interrupt the Erlang shell,\n");
+    erts_fprintf(stderr, "               d (or no extra option) to disable the break\n");
+    erts_fprintf(stderr, "               handler, i to ignore break signals\n");
 
     /*    erts_fprintf(stderr, "-b func    set the boot function (default boot)\n"); */
 
-    erts_fprintf(stderr, "-c          disable continuous date/time correction with\n");
-    erts_fprintf(stderr, "            respect to uptime\n");
+    erts_fprintf(stderr, "-c             disable continuous date/time correction with\n");
+    erts_fprintf(stderr, "               respect to uptime\n");
 
-    erts_fprintf(stderr, "-d          don't write a crash dump for internally detected errors\n");
-    erts_fprintf(stderr, "            (halt(String) will still produce a crash dump)\n");
-    erts_fprintf(stderr, "-fn[u|a|l]  Control how filenames are interpreted\n");
-    erts_fprintf(stderr, "-hms size   set minimum heap size in words (default %d)\n",
+    erts_fprintf(stderr, "-d             don't write a crash dump for internally detected errors\n");
+    erts_fprintf(stderr, "               (halt(String) will still produce a crash dump)\n");
+    erts_fprintf(stderr, "-fn[u|a|l]     Control how filenames are interpreted\n");
+    erts_fprintf(stderr, "-hms size      set minimum heap size in words (default %d)\n",
 	       H_DEFAULT_SIZE);
-    erts_fprintf(stderr, "-hmbs size  set minimum binary virtual heap size in words (default %d)\n",
+    erts_fprintf(stderr, "-hmbs size     set minimum binary virtual heap size in words (default %d)\n",
 	       VH_DEFAULT_SIZE);
 
     /*    erts_fprintf(stderr, "-i module  set the boot module (default init)\n"); */
 
-    erts_fprintf(stderr, "-K boolean  enable or disable kernel poll\n");
-    erts_fprintf(stderr, "-n[s|a|d]   Control behavior of signals to ports\n");
-    erts_fprintf(stderr, "            Note that this flag is deprecated!\n");
-    erts_fprintf(stderr, "-M<X> <Y>   memory allocator switches,\n");
-    erts_fprintf(stderr, "            see the erts_alloc(3) documentation for more info.\n");
-    erts_fprintf(stderr, "-pc <set>   Control what characters are considered printable (default latin1)\n");
-    erts_fprintf(stderr, "-P number   set maximum number of processes on this node,\n");
-    erts_fprintf(stderr, "            valid range is [%d-%d]\n",
+    erts_fprintf(stderr, "-K boolean     enable or disable kernel poll\n");
+    erts_fprintf(stderr, "-n[s|a|d]      Control behavior of signals to ports\n");
+    erts_fprintf(stderr, "               Note that this flag is deprecated!\n");
+    erts_fprintf(stderr, "-M<X> <Y>      memory allocator switches,\n");
+    erts_fprintf(stderr, "               see the erts_alloc(3) documentation for more info.\n");
+    erts_fprintf(stderr, "-pc <set>      Control what characters are considered printable (default latin1)\n");
+    erts_fprintf(stderr, "-P number      set maximum number of processes on this node,\n");
+    erts_fprintf(stderr, "               valid range is [%d-%d]\n",
 		 ERTS_MIN_PROCESSES, ERTS_MAX_PROCESSES);
-    erts_fprintf(stderr, "-Q number   set maximum number of ports on this node,\n");
-    erts_fprintf(stderr, "            valid range is [%d-%d]\n",
+    erts_fprintf(stderr, "-Q number      set maximum number of ports on this node,\n");
+    erts_fprintf(stderr, "               valid range is [%d-%d]\n",
 		 ERTS_MIN_PORTS, ERTS_MAX_PORTS);
-    erts_fprintf(stderr, "-R number   set compatibility release number,\n");
-    erts_fprintf(stderr, "            valid range [%d-%d]\n",
+    erts_fprintf(stderr, "-R number      set compatibility release number,\n");
+    erts_fprintf(stderr, "               valid range [%d-%d]\n",
 		 this_rel-2, this_rel);
 
-    erts_fprintf(stderr, "-r          force ets memory block to be moved on realloc\n");
-    erts_fprintf(stderr, "-rg amount  set reader groups limit\n");
-    erts_fprintf(stderr, "-sbt type   set scheduler bind type, valid types are:\n");
-    erts_fprintf(stderr, "-stbt type  u|ns|ts|ps|s|nnts|nnps|tnnps|db\n");
-    erts_fprintf(stderr, "-sbwt val   set scheduler busy wait threshold, valid values are:\n");
-    erts_fprintf(stderr, "            none|very_short|short|medium|long|very_long.\n");
-    erts_fprintf(stderr, "-scl bool   enable/disable compaction of scheduler load,\n");
-    erts_fprintf(stderr, "            see the erl(1) documentation for more info.\n");
-    erts_fprintf(stderr, "-sct cput   set cpu topology,\n");
-    erts_fprintf(stderr, "            see the erl(1) documentation for more info.\n");
+    erts_fprintf(stderr, "-r             force ets memory block to be moved on realloc\n");
+    erts_fprintf(stderr, "-rg amount     set reader groups limit\n");
+    erts_fprintf(stderr, "-sbt type      set scheduler bind type, valid types are:\n");
+    erts_fprintf(stderr, "-stbt type     u|ns|ts|ps|s|nnts|nnps|tnnps|db\n");
+    erts_fprintf(stderr, "-sbwt val      set scheduler busy wait threshold, valid values are:\n");
+    erts_fprintf(stderr, "               none|very_short|short|medium|long|very_long.\n");
+    erts_fprintf(stderr, "-scl bool      enable/disable compaction of scheduler load,\n");
+    erts_fprintf(stderr, "               see the erl(1) documentation for more info.\n");
+    erts_fprintf(stderr, "-sct cput      set cpu topology,\n");
+    erts_fprintf(stderr, "               see the erl(1) documentation for more info.\n");
 #if ERTS_HAVE_SCHED_UTIL_BALANCING_SUPPORT_OPT
-    erts_fprintf(stderr, "-sub bool   enable/disable scheduler utilization balancing,\n");
+    erts_fprintf(stderr, "-sub bool      enable/disable scheduler utilization balancing,\n");
 #else
-    erts_fprintf(stderr, "-sub false  disable scheduler utilization balancing,\n");
+    erts_fprintf(stderr, "-sub false     disable scheduler utilization balancing,\n");
 #endif
-    erts_fprintf(stderr, "            see the erl(1) documentation for more info.\n");
-    erts_fprintf(stderr, "-sws val    set scheduler wakeup strategy, valid values are:\n");
-    erts_fprintf(stderr, "            default|legacy.\n");
-    erts_fprintf(stderr, "-swct val   set scheduler wake cleanup threshold, valid values are:\n");
-    erts_fprintf(stderr, "            very_lazy|lazy|medium|eager|very_eager.\n");
-    erts_fprintf(stderr, "-swt val    set scheduler wakeup threshold, valid values are:\n");
-    erts_fprintf(stderr, "            very_low|low|medium|high|very_high.\n");
-    erts_fprintf(stderr, "-sss size   suggested stack size in kilo words for scheduler threads,\n");
-    erts_fprintf(stderr, "            valid range is [%d-%d]\n",
+    erts_fprintf(stderr, "               see the erl(1) documentation for more info.\n");
+    erts_fprintf(stderr, "-sws val       set scheduler wakeup strategy, valid values are:\n");
+    erts_fprintf(stderr, "               default|legacy.\n");
+    erts_fprintf(stderr, "-swct val      set scheduler wake cleanup threshold, valid values are:\n");
+    erts_fprintf(stderr, "               very_lazy|lazy|medium|eager|very_eager.\n");
+    erts_fprintf(stderr, "-swt val       set scheduler wakeup threshold, valid values are:\n");
+    erts_fprintf(stderr, "               very_low|low|medium|high|very_high.\n");
+    erts_fprintf(stderr, "-sss size      suggested stack size in kilo words for scheduler threads,\n");
+    erts_fprintf(stderr, "               valid range is [%d-%d]\n",
 		 ERTS_SCHED_THREAD_MIN_STACK_SIZE,
 		 ERTS_SCHED_THREAD_MAX_STACK_SIZE);
-    erts_fprintf(stderr, "-spp Bool   set port parallelism scheduling hint\n");
-    erts_fprintf(stderr, "-S n1:n2    set number of schedulers (n1), and number of\n");
-    erts_fprintf(stderr, "            schedulers online (n2), maximum for both\n");
-    erts_fprintf(stderr, "            numbers is %d\n",
+    erts_fprintf(stderr, "-spp Bool      set port parallelism scheduling hint\n");
+    erts_fprintf(stderr, "-S n1:n2       set number of schedulers (n1), and number of\n");
+    erts_fprintf(stderr, "               schedulers online (n2), maximum for both\n");
+    erts_fprintf(stderr, "               numbers is %d\n",
 		 ERTS_MAX_NO_OF_SCHEDULERS);
-    erts_fprintf(stderr, "-SP p1:p2   specify schedulers (p1) and schedulers online (p2)\n");
-    erts_fprintf(stderr, "            as percentages of logical processors configured and logical\n");
-    erts_fprintf(stderr, "            processors available, respectively\n");
-    erts_fprintf(stderr, "-t size     set the maximum number of atoms the "
-			 "emulator can handle\n");
-    erts_fprintf(stderr, "            valid range is [%d-%d]\n",
+    erts_fprintf(stderr, "-SP p1:p2      specify schedulers (p1) and schedulers online (p2)\n");
+    erts_fprintf(stderr, "               as percentages of logical processors configured and logical\n");
+    erts_fprintf(stderr, "               processors available, respectively\n");
+#ifdef ERTS_DIRTY_SCHEDULERS
+    erts_fprintf(stderr, "-SDcpu n1:n2   set number of dirty CPU schedulers (n1), and number of\n");
+    erts_fprintf(stderr, "               dirty CPU schedulers online (n2), valid range for both\n");
+    erts_fprintf(stderr, "               numbers is [1-%d], and n2 must be less than or equal to n1\n",
+		 ERTS_MAX_NO_OF_DIRTY_CPU_SCHEDULERS);
+    erts_fprintf(stderr, "-SDPcpu p1:p2  specify dirty CPU schedulers (p1) and dirty CPU schedulers\n");
+    erts_fprintf(stderr, "               online (p2) as percentages of logical processors configured\n");
+    erts_fprintf(stderr, "               and logical processors available, respectively\n");
+    erts_fprintf(stderr, "-SDio n        set number of dirty I/O schedulers, valid range is [0-%d]\n",
+		 ERTS_MAX_NO_OF_DIRTY_IO_SCHEDULERS);
+#endif
+    erts_fprintf(stderr, "-t size        set the maximum number of atoms the emulator can handle\n");
+    erts_fprintf(stderr, "               valid range is [%d-%d]\n",
 		 MIN_ATOM_TABLE_SIZE, MAX_ATOM_TABLE_SIZE);
-    erts_fprintf(stderr, "-T number   set modified timing level,\n");
-    erts_fprintf(stderr, "            valid range is [0-%d]\n",
+    erts_fprintf(stderr, "-T number      set modified timing level, valid range is [0-%d]\n",
 		 ERTS_MODIFIED_TIMING_LEVELS-1);
-    erts_fprintf(stderr, "-V          print Erlang version\n");
+    erts_fprintf(stderr, "-V             print Erlang version\n");
 
-    erts_fprintf(stderr, "-v          turn on chatty mode (GCs will be reported etc)\n");
+    erts_fprintf(stderr, "-v             turn on chatty mode (GCs will be reported etc)\n");
 
-    erts_fprintf(stderr, "-W<i|w>     set error logger warnings mapping,\n");
-    erts_fprintf(stderr, "            see error_logger documentation for details\n");
-    erts_fprintf(stderr, "-zdbbl size set the distribution buffer busy limit in kilobytes\n");
-    erts_fprintf(stderr, "            valid range is [1-%d]\n", INT_MAX/1024);
+    erts_fprintf(stderr, "-W<i|w>        set error logger warnings mapping,\n");
+    erts_fprintf(stderr, "               see error_logger documentation for details\n");
+    erts_fprintf(stderr, "-zdbbl size    set the distribution buffer busy limit in kilobytes\n");
+    erts_fprintf(stderr, "               valid range is [1-%d]\n", INT_MAX/1024);
     erts_fprintf(stderr, "\n");
     erts_fprintf(stderr, "Note that if the emulator is started with erlexec (typically\n");
     erts_fprintf(stderr, "from the erl script), these flags should be specified with +.\n");
@@ -643,6 +652,13 @@ early_init(int *argc, char **argv) /*
     int schdlrs_percentage = 100;
     int schdlrs_onln_percentage = 100;
     int max_main_threads;
+#ifdef ERTS_DIRTY_SCHEDULERS
+    int dirty_cpu_scheds;
+    int dirty_cpu_scheds_online;
+    int dirty_cpu_scheds_pctg = 100;
+    int dirty_cpu_scheds_onln_pctg = 100;
+    int dirty_io_scheds;
+#endif
     int max_reader_groups;
     int reader_groups;
     char envbuf[21]; /* enough for any 64-bit integer */
@@ -718,6 +734,12 @@ early_init(int *argc, char **argv) /*
     schdlrs = no_schedulers;
     schdlrs_onln = no_schedulers_online;
 
+#ifdef ERTS_DIRTY_SCHEDULERS
+    dirty_cpu_scheds = no_schedulers;
+    dirty_cpu_scheds_online = no_schedulers_online;
+    dirty_io_scheds = 10;
+#endif
+
     envbufsz = sizeof(envbuf);
 
     /* erts_sys_getenv(_raw)() not initialized yet; need erts_sys_getenv__() */
@@ -808,7 +830,121 @@ early_init(int *argc, char **argv) /*
                         VERBOSE(DEBUG_SYSTEM,
                                 ("using %d:%d scheduler percentages\n",
                                  schdlrs_percentage, schdlrs_onln_percentage));
-                    } else {
+                    }
+#ifdef ERTS_DIRTY_SCHEDULERS
+		    else if (argv[i][2] == 'D') {
+			char *arg;
+			char *type = argv[i]+3;
+			if (strcmp(type, "Pcpu") == 0) {
+			    int ptot, ponln;
+			    arg = get_arg(argv[i]+7, argv[i+1], &i);
+			    switch (sscanf(arg, "%d:%d", &ptot, &ponln)) {
+			    case 0:
+				switch (sscanf(arg, ":%d", &ponln)) {
+				case 1:
+				    if (ponln < 0)
+					goto bad_SDPcpu;
+				    ptot = 100;
+				    goto chk_SDPcpu;
+				default:
+				    goto bad_SDPcpu;
+				}
+			    case 1:
+				if (ptot < 0)
+				    goto bad_SDPcpu;
+				ponln = ptot < 100 ? ptot : 100;
+				goto chk_SDPcpu;
+			    case 2:
+				if (ptot < 0 || ponln < 0)
+				    goto bad_SDPcpu;
+			    chk_SDPcpu:
+				dirty_cpu_scheds_pctg = ptot;
+				dirty_cpu_scheds_onln_pctg = ponln;
+				break;
+			    default:
+			    bad_SDPcpu:
+				erts_fprintf(stderr,
+					     "bad dirty CPU schedulers percentage specifier %s\n",
+					     arg);
+				erts_usage();
+				break;
+			    }
+			    VERBOSE(DEBUG_SYSTEM,
+				    ("using %d:%d dirty CPU scheduler percentages\n",
+				     dirty_cpu_scheds_pctg, dirty_cpu_scheds_onln_pctg));
+			} else if (strcmp(type, "cpu") == 0) {
+			    int tot, onln;
+			    arg = get_arg(argv[i]+6, argv[i+1], &i);
+			    switch (sscanf(arg, "%d:%d", &tot, &onln)) {
+			    case 0:
+				switch (sscanf(arg, ":%d", &onln)) {
+				case 1:
+				    tot = no_schedulers;
+				    goto chk_SDcpu;
+				default:
+				    goto bad_SDcpu;
+				}
+			    case 1:
+				onln = tot < dirty_cpu_scheds_online ?
+				    tot : dirty_cpu_scheds_online;
+			    case 2:
+			    chk_SDcpu:
+				if (tot > 0)
+				    dirty_cpu_scheds = tot;
+				else
+				    dirty_cpu_scheds = no_schedulers + tot;
+				if (onln > 0)
+				    dirty_cpu_scheds_online = onln;
+				else
+				    dirty_cpu_scheds_online = no_schedulers_online + onln;
+				if (dirty_cpu_scheds < 1 ||
+				    ERTS_MAX_NO_OF_DIRTY_CPU_SCHEDULERS < dirty_cpu_scheds) {
+				    erts_fprintf(stderr,
+						 "bad amount of dirty CPU schedulers %d\n",
+						 tot);
+				    erts_usage();
+				}
+				if (dirty_cpu_scheds_online < 1 ||
+				    dirty_cpu_scheds < dirty_cpu_scheds_online) {
+				    erts_fprintf(stderr,
+						 "bad amount of dirty CPU schedulers online %d "
+						 "(total amount of dirty CPU schedulers %d)\n",
+						 dirty_cpu_scheds_online, dirty_cpu_scheds);
+				    erts_usage();
+				}
+				break;
+			    default:
+			    bad_SDcpu:
+				erts_fprintf(stderr,
+					     "bad amount of dirty CPU schedulers %s\n",
+					     arg);
+				erts_usage();
+				break;
+			    }
+			    VERBOSE(DEBUG_SYSTEM,
+				    ("using %d:%d dirty CPU scheduler(s)\n", tot, onln));
+			} else if (strcmp(type, "io") == 0) {
+			    arg = get_arg(argv[i]+5, argv[i+1], &i);
+			    dirty_io_scheds = atoi(arg);
+			    if (dirty_io_scheds < 0 ||
+				dirty_io_scheds > ERTS_MAX_NO_OF_DIRTY_IO_SCHEDULERS) {
+				erts_fprintf(stderr,
+					     "bad number of dirty I/O schedulers %s\n",
+					     arg);
+				erts_usage();
+			    }
+			    VERBOSE(DEBUG_SYSTEM,
+				    ("using %d dirty I/O scheduler(s)\n", dirty_io_scheds));
+			} else {
+			    erts_fprintf(stderr,
+					 "bad or missing dirty scheduler specifier: %s\n",
+					 argv[i]);
+			    erts_usage();
+			    break;
+			}
+		    }
+#endif
+		    else {
 			int tot, onln;
 			char *arg = get_arg(argv[i]+2, argv[i+1], &i);
 			switch (sscanf(arg, "%d:%d", &tot, &onln)) {
@@ -895,6 +1031,17 @@ early_init(int *argc, char **argv) /*
 	(void)schdlrs_percentage;
 	(void)schdlrs_onln_percentage;
 #endif
+#ifdef ERTS_DIRTY_SCHEDULERS
+	/* apply any dirty scheduler precentages */
+	if (dirty_cpu_scheds_pctg != 100 || dirty_cpu_scheds_onln_pctg != 100) {
+	    dirty_cpu_scheds = dirty_cpu_scheds * dirty_cpu_scheds_pctg / 100;
+	    dirty_cpu_scheds_online = dirty_cpu_scheds_online * dirty_cpu_scheds_onln_pctg / 100;
+	}
+	if (dirty_cpu_scheds > schdlrs)
+	    dirty_cpu_scheds = schdlrs;
+	if (dirty_cpu_scheds_online > schdlrs_onln)
+	    dirty_cpu_scheds_online = schdlrs_onln;
+#endif
     }
 
 #ifndef USE_THREADS
@@ -907,6 +1054,11 @@ early_init(int *argc, char **argv) /*
 
     erts_no_schedulers = (Uint) no_schedulers;
 #endif
+#ifdef ERTS_DIRTY_SCHEDULERS
+    erts_no_dirty_cpu_schedulers = dirty_cpu_scheds;
+    erts_no_dirty_cpu_schedulers_online = dirty_cpu_scheds_online;
+    erts_no_dirty_io_schedulers = dirty_io_scheds;
+#endif
     erts_early_init_scheduling(no_schedulers);
 
     alloc_opts.ncpu = ncpu;
@@ -924,10 +1076,18 @@ early_init(int *argc, char **argv) /*
      *
      * * Unmanaged threads that need to register:
      * ** Async threads (see erl_async.c)
+     * ** Dirty scheduler threads
      */
     erts_thr_progress_init(no_schedulers,
 			   no_schedulers+2,
-			   erts_async_max_threads);
+#ifndef ERTS_DIRTY_SCHEDULERS
+			   erts_async_max_threads
+#else
+			   erts_async_max_threads +
+			   erts_no_dirty_cpu_schedulers +
+			   erts_no_dirty_io_schedulers
+#endif
+			   );
 #endif
     erts_thr_q_init();
     erts_init_utils();
@@ -1392,7 +1552,15 @@ erl_start(int argc, char **argv)
 	    break;
 
 	case 'S' : /* Was handled in early_init() just read past it */
-	    if (argv[i][2] == 'P')
+	    if (argv[i][2] == 'D') {
+		char* type = argv[i]+3;
+		if (strcmp(type, "Pcpu") == 0)
+		    (void) get_arg(argv[i]+7, argv[i+1], &i);
+		if (strcmp(type, "cpu") == 0)
+		    (void) get_arg(argv[i]+6, argv[i+1], &i);
+		else if (strcmp(type, "io") == 0)
+		    (void) get_arg(argv[i]+5, argv[i+1], &i);
+	    } else if (argv[i][2] == 'P')
 		(void) get_arg(argv[i]+3, argv[i+1], &i);
 	    else
 		(void) get_arg(argv[i]+2, argv[i+1], &i);