system_cmds-880.100.5.tar.gz

[apple/system_cmds.git] / iosim.tproj / iosim.c

diff --git a/iosim.tproj/iosim.c b/iosim.tproj/iosim.c
index 349b9c891b00c66764bcb7d3d3bae5771ff56070..7a0efce7ea8c81551b546679c9a0452864c1ad67 100644 (file)
--- a/iosim.tproj/iosim.c
+++ b/iosim.tproj/iosim.c
@@ -14,57 +14,77 @@
 #include <libkern/OSAtomic.h>
 #include <limits.h>
 #include <errno.h>
 #include <libkern/OSAtomic.h>
 #include <limits.h>
 #include <errno.h>

-
-#define IO_MODE_SEQ            0
-#define IO_MODE_RANDOM                 1
-
-#define WORKLOAD_TYPE_RO       0
-#define WORKLOAD_TYPE_WO       1
-#define WORKLOAD_TYPE_RW       2
-
-#define MAX_THREADS            1000
-#define MAX_FILENAME           64
-#define MAX_ITERATIONS                 10000
-#define LATENCY_BIN_SIZE       500
-#define LATENCY_BINS           11      
-#define LOW_LATENCY_BIN_SIZE   50
-#define LOW_LATENCY_BINS       11
+#include <CoreFoundation/CoreFoundation.h>
+#include "panic.h"
+#include <IOKit/IOKitLib.h>
+#include <spawn.h>
+
+#define IO_MODE_SEQ            0
+#define IO_MODE_RANDOM         1
+
+#define WORKLOAD_TYPE_RO       0
+#define WORKLOAD_TYPE_WO       1
+#define WORKLOAD_TYPE_RW       2
+
+#define MAX_THREADS            1000
+#define MAX_FILENAME           64
+#define MAX_ITERATIONS         10000
+#define LATENCY_BIN_SIZE       1000
+#define LATENCY_BINS           31
+#define LOW_LATENCY_BIN_SIZE   50
+#define LOW_LATENCY_BINS       21

 #define THROUGHPUT_INTERVAL    5000
 #define THROUGHPUT_INTERVAL    5000

-#define DEFAULT_FILE_SIZE      (262144)
-#define BLOCKSIZE              1024
-#define MAX_CMD_SIZE           256
-#define PG_MASK                ~(0xFFF)
-
-int burst_count = 10;                  /* Unit: Number ; Desc.: I/O Burst Count */
-int inter_burst_duration = 0;          /* Unit: msecs  ; Desc.: I/O Inter-Burst Duration (-1: Random value [0,100]) */
-int inter_io_delay_ms = 0;             /* Unit: msecs  ; Desc.: Inter I/O Delay */
-int thread_count = 1;                  /* Unit: Number ; Desc.: Thread Count */
+#define DEFAULT_FILE_SIZE      (262144)
+#define BLOCKSIZE              1024
+#define MAX_CMD_SIZE           256
+#define PG_MASK                        ~(0xFFF)
+#define kIONVMeANS2ControllerString         "AppleANS2Controller"
+#define kIONVMeANS2EmbeddedControllerString "AppleANS2NVMeController"
+#define kIONVMeControllerString             "AppleNVMeController"
+
+typedef enum {
+       kDefaultDevice    = 0,
+       kNVMeDevice       = 1,
+       kNVMeDeviceANS2   = 2,
+} qos_device_type_t;
+
+int burst_count = 10;                  /* Unit: Number ; Desc.: I/O Burst Count */
+int inter_burst_duration = 0;          /* Unit: msecs  ; Desc.: I/O Inter-Burst Duration (-1: Random value [0,100]) */
+int inter_io_delay_ms = 0;             /* Unit: msecs  ; Desc.: Inter I/O Delay */
+int thread_count = 1;                  /* Unit: Number ; Desc.: Thread Count */

 int workload_type = WORKLOAD_TYPE_RO;  /* Unit: 0/1/2  ; Desc.: Workload Type */
 int workload_type = WORKLOAD_TYPE_RO;  /* Unit: 0/1/2  ; Desc.: Workload Type */

-int io_size = 4096;                    /* Unit: Bytes  ; Desc.: I/O Unit Size */
-int sync_frequency_ms = 0;             /* Unit: msecs  ; Desc.: Sync thread frequency (0: Indicates no sync) */
-int io_mode = 0;                       /* Unit: 0/1    ; Desc.: I/O Mode (Seq./Rand.) */
+int io_size = 4096;                    /* Unit: Bytes  ; Desc.: I/O Unit Size */
+int sync_frequency_ms = 0;             /* Unit: msecs  ; Desc.: Sync thread frequency (0: Indicates no sync) */
+int io_mode = 0;                       /* Unit: 0/1    ; Desc.: I/O Mode (Seq./Rand.) */

 int test_duration = 0;                  /* Unit: secs   ; Desc.: Total Test Duration (0 indicates wait for Ctrl+C signal) */
 int test_duration = 0;                  /* Unit: secs   ; Desc.: Total Test Duration (0 indicates wait for Ctrl+C signal) */

-int io_tier = 0;                       /* Unit: 0/1/2/3; Desc.: I/O Tier */
-int file_size = DEFAULT_FILE_SIZE;     /* Unit: pages  ; Desc.: File Size in 4096 byte blocks */
-int cached_io_flag = 0;                /* Unit: 0/1    ; Desc.: I/O Caching behavior (no-cached/cached) */
-char *user_fname; 
+int io_tier = 0;                       /* Unit: 0/1/2/3; Desc.: I/O Tier */
+int file_size = DEFAULT_FILE_SIZE;     /* Unit: pages  ; Desc.: File Size in 4096 byte blocks */
+int cached_io_flag = 0;                        /* Unit: 0/1    ; Desc.: I/O Caching behavior (no-cached/cached) */
+int io_qos_timeout_ms = 0;             /* Unit: msecs  ; Desc.: I/O QOS timeout */
+char *user_fname;

 int user_specified_file = 0;
 int user_specified_file = 0;

+qos_device_type_t qos_device = 0;

 
 

-int64_t total_io_count;
-int64_t total_io_size;
-int64_t total_io_time;
-int64_t total_burst_count;
+int64_t total_io_count = 0;
+int64_t total_io_size = 0;
+int64_t total_io_time = 0;
+int64_t max_io_time = 0;
+int64_t total_burst_count = 0;

 int64_t latency_histogram[LATENCY_BINS];
 int64_t burst_latency_histogram[LATENCY_BINS];
 int64_t low_latency_histogram[LOW_LATENCY_BINS];
 int64_t throughput_histogram[MAX_ITERATIONS];
 int64_t throughput_index;
 int64_t latency_histogram[LATENCY_BINS];
 int64_t burst_latency_histogram[LATENCY_BINS];
 int64_t low_latency_histogram[LOW_LATENCY_BINS];
 int64_t throughput_histogram[MAX_ITERATIONS];
 int64_t throughput_index;

+CFRunLoopTimerRef      runLoopTimer    = NULL;

 
 void print_usage(void);
 
 void print_usage(void);

-void print_data_percentage(int percent);
+void print_data_percentage(double percent);

 void print_stats(void);
 unsigned int find_io_bin(int64_t latency, int latency_bin_size, int latency_bins);
 void signalHandler(int sig);
 void print_stats(void);
 unsigned int find_io_bin(int64_t latency, int latency_bin_size, int latency_bins);
 void signalHandler(int sig);

+void assertASP(CFRunLoopTimerRef timer, void *info );
+void start_qos_timer(void);
+void stop_qos_timer(void);

 void perform_io(int fd, char *buf, int size, int type);
 void *sync_routine(void *arg);
 void *calculate_throughput(void *arg);
 void perform_io(int fd, char *buf, int size, int type);
 void *sync_routine(void *arg);
 void *calculate_throughput(void *arg);


@@ -72,9 +92,12 @@ void *io_routine(void *arg);
 void validate_option(int value, int min, int max, char *option, char *units);
 void print_test_setup(int value, char *option, char *units, char *comment);
 void setup_process_io_policy(int io_tier);
 void validate_option(int value, int min, int max, char *option, char *units);
 void print_test_setup(int value, char *option, char *units, char *comment);
 void setup_process_io_policy(int io_tier);

-void print_latency_histogram(int64_t *data, int latency_bins, int latency_bin_size);
+void setup_qos_device(void);
+void print_latency_histogram(int64_t *data, int latency_bins, int latency_bin_size, double io_count);
+int system_cmd(char *command);

 
 

-void print_usage()
+void
+print_usage(void)

 {
        printf("Usage: ./iosim [options]\n");
        printf("Options:\n");
 {
        printf("Usage: ./iosim [options]\n");
        printf("Options:\n");


@@ -91,9 +114,10 @@ void print_usage()
        printf("-z: (number)  File Size in pages (1 page = 4096 bytes) \n");
        printf("-n: (string)  File name used for tests (the tool would create files if this option is not specified)\n");
        printf("-a: (0/1   :  Non-cached/Cached) I/O Caching behavior\n");
        printf("-z: (number)  File Size in pages (1 page = 4096 bytes) \n");
        printf("-n: (string)  File name used for tests (the tool would create files if this option is not specified)\n");
        printf("-a: (0/1   :  Non-cached/Cached) I/O Caching behavior\n");

+       printf("-q: (msecs)   I/O QoS timeout. Time of I/O before drive assert and system panic\n");

 }
 
 }
 

-void print_data_percentage(int percent)
+void print_data_percentage(double percent)

 {
        int count = (int)(round(percent / 5.0));
        int spaces = 20 - count;
 {
        int count = (int)(round(percent / 5.0));
        int spaces = 20 - count;


@@ -105,7 +129,7 @@ void print_data_percentage(int percent)
        printf("|");
 }
 
        printf("|");
 }
 

-void print_latency_histogram(int64_t *data, int latency_bins, int latency_bin_size)
+void print_latency_histogram(int64_t *data, int latency_bins, int latency_bin_size, double io_count)

 {
        double percentage;
         char label[MAX_FILENAME];
 {
        double percentage;
         char label[MAX_FILENAME];


@@ -117,9 +141,9 @@ void print_latency_histogram(int64_t *data, int latency_bins, int latency_bin_si
                 else
                         snprintf(label, MAX_FILENAME, "%d - %d usecs", i * latency_bin_size, (i+1) * latency_bin_size);
                 printf("%25s ", label);
                 else
                         snprintf(label, MAX_FILENAME, "%d - %d usecs", i * latency_bin_size, (i+1) * latency_bin_size);
                 printf("%25s ", label);

-                percentage = ((double)data[i] * 100.0) / (double)total_io_count;
-                print_data_percentage((int)percentage);
-                printf(" %.2lf%%\n", percentage);
+                percentage = ((double)data[i] * 100.000000) / io_count;
+                print_data_percentage(percentage);
+                printf(" %.6lf%%\n", percentage);

         }
        printf("\n");
 }
         }
        printf("\n");
 }


@@ -133,15 +157,16 @@ void print_stats()
        printf("I/O Statistics:\n");
 
        printf("Total I/Os      : %lld\n", total_io_count);
        printf("I/O Statistics:\n");
 
        printf("Total I/Os      : %lld\n", total_io_count);

-       printf("Avg. Latency    : %.2lf usecs\n", ((double)total_io_time) / ((double)total_io_count));  
+       printf("Avg. Latency    : %.2lf usecs\n", ((double)total_io_time) / ((double)total_io_count));
+       printf("Max. Latency    : %.2lf usecs\n", ((double)max_io_time));

 
        printf("Low Latency Histogram: \n");
 
        printf("Low Latency Histogram: \n");

-       print_latency_histogram(low_latency_histogram, LOW_LATENCY_BINS, LOW_LATENCY_BIN_SIZE);
+       print_latency_histogram(low_latency_histogram, LOW_LATENCY_BINS, LOW_LATENCY_BIN_SIZE, (double)total_io_count);

        printf("Latency Histogram: \n");
        printf("Latency Histogram: \n");

-       print_latency_histogram(latency_histogram, LATENCY_BINS, LATENCY_BIN_SIZE);
+       print_latency_histogram(latency_histogram, LATENCY_BINS, LATENCY_BIN_SIZE, (double)total_io_count);

        printf("Burst Avg. Latency Histogram: \n");
        printf("Burst Avg. Latency Histogram: \n");

-       print_latency_histogram(burst_latency_histogram, LATENCY_BINS, LATENCY_BIN_SIZE);
-       
+       print_latency_histogram(burst_latency_histogram, LATENCY_BINS, LATENCY_BIN_SIZE, (double)total_burst_count);
+

        printf("Throughput Timeline: \n");
 
        int64_t max_throughput = 0;
        printf("Throughput Timeline: \n");
 
        int64_t max_throughput = 0;


@@ -158,7 +183,6 @@ void print_stats()
                printf("%.2lf MBps\n", ((double)throughput_histogram[i] / 1048576.0) / ((double)THROUGHPUT_INTERVAL / 1000.0));
        }
        printf("\n");
                printf("%.2lf MBps\n", ((double)throughput_histogram[i] / 1048576.0) / ((double)THROUGHPUT_INTERVAL / 1000.0));
        }
        printf("\n");

-               

 }
 
 unsigned int find_io_bin(int64_t latency, int latency_bin_size, int latency_bins)
 }
 
 unsigned int find_io_bin(int64_t latency, int latency_bin_size, int latency_bins)


@@ -176,6 +200,106 @@ void signalHandler(int sig)
        exit(0);
 }
 
        exit(0);
 }
 

+void setup_qos_device(void)
+{
+       kern_return_t           status          = kIOReturnError;
+       io_iterator_t       iterator    = IO_OBJECT_NULL;
+
+       if(io_qos_timeout_ms <= 0)
+               return;
+
+       printf ( "*** setup_qos_device *** \n" );
+
+       status = IOServiceGetMatchingServices ( kIOMasterPortDefault, IOServiceMatching ( kIONVMeANS2ControllerString ), &iterator );
+
+       if ( status != kIOReturnSuccess )
+               return;
+
+       if ( iterator != IO_OBJECT_NULL ) {
+               printf ( "Found NVMe ANS2 Device \n" );
+               qos_device = kNVMeDeviceANS2;
+               return;
+       }
+
+       status = IOServiceGetMatchingServices ( kIOMasterPortDefault, IOServiceMatching ( kIONVMeANS2EmbeddedControllerString ), &iterator );
+
+       if ( status != kIOReturnSuccess )
+               return;
+
+       if ( iterator != IO_OBJECT_NULL ) {
+               printf ( "Found NVMe ANS2 Embedded Device \n" );
+               qos_device = kNVMeDeviceANS2;
+               return;
+       }
+
+       status= IOServiceGetMatchingServices ( kIOMasterPortDefault, IOServiceMatching ( kIONVMeControllerString ), &iterator );
+
+       if ( status != kIOReturnSuccess )
+               return;
+
+       if ( iterator != IO_OBJECT_NULL ) {
+               printf ( "Found NVMe Device \n" );
+               qos_device = kNVMeDevice;
+               return;
+       }
+
+       printf ( "NVMe Device not found, not setting qos timeout\n" );
+       qos_device = kDefaultDevice;
+       return;
+}
+
+void assertASP(CFRunLoopTimerRef timer, void *info )
+{
+       char command [ 1024 ];
+
+       if(qos_device == kDefaultDevice)
+               return;
+
+       printf("assertASP. Timeout of IO exceeds = %d msec\n", io_qos_timeout_ms);
+
+       // kNVMe_ANS2_Force_Assert_offset               = 0x13EC, // GP59
+       // kNVMe_Force_Assert_Offset                = 0x550,
+
+       if(qos_device == kNVMeDeviceANS2)
+               snprintf ( command, sizeof ( command ), "/usr/local/bin/nvmectl-tool.py -a WriteRegister32 $((0x13EC)) 0xFFFF" );
+       else if(qos_device == kNVMeDevice)
+               snprintf ( command, sizeof ( command ), "/usr/local/bin/nvmectl-tool.py -a WriteRegister32 $((0x550)) 0xFFFF" );
+       else
+               return;
+
+       // Assert ASP
+       printf("Command : %s\n", command);
+       system_cmd(command);
+
+       // Panic the system as well
+       panic("IO time > QoS timeout");
+
+       return;
+}
+
+void start_qos_timer(void)
+{
+       float timeout_sec;
+
+       if(io_qos_timeout_ms <= 0)
+               return;
+
+       timeout_sec = (float)io_qos_timeout_ms/1000;
+
+       // Schedule a "timeout" delayed task that checks IO's which take > timeout sec to complete
+       runLoopTimer = CFRunLoopTimerCreate(NULL, CFAbsoluteTimeGetCurrent()+timeout_sec, 0, 0, 0, assertASP, NULL);
+       CFRunLoopAddTimer(CFRunLoopGetMain(), runLoopTimer, kCFRunLoopDefaultMode);
+}
+
+void stop_qos_timer(void)
+{
+       if(runLoopTimer == NULL)
+               return;
+
+       CFRunLoopTimerInvalidate(runLoopTimer);
+       CFRunLoopRemoveTimer(CFRunLoopGetMain(), runLoopTimer, kCFRunLoopDefaultMode);
+       CFRelease(runLoopTimer);
+}

 
 void perform_io(int fd, char *buf, int size, int type)
 {
 
 void perform_io(int fd, char *buf, int size, int type)
 {


@@ -190,14 +314,14 @@ void perform_io(int fd, char *buf, int size, int type)
                        ret = read(fd, buf, size);
                else
                        ret = write(fd, buf, size);
                        ret = read(fd, buf, size);
                else
                        ret = write(fd, buf, size);

-       
+

                if (ret == 0) {
                        if (lseek(fd, 0, SEEK_SET) < 0) {
                                perror("lseek() to reset file offset to zero failed!\n");
                                goto error;
                        }
                }
                if (ret == 0) {
                        if (lseek(fd, 0, SEEK_SET) < 0) {
                                perror("lseek() to reset file offset to zero failed!\n");
                                goto error;
                        }
                }

-               
+

                if (ret < 0) {
                        perror("read/write syscall failed!\n");
                        goto error;
                if (ret < 0) {
                        perror("read/write syscall failed!\n");
                        goto error;


@@ -214,7 +338,7 @@ error:
 
 void *sync_routine(void *arg)
 {
 
 void *sync_routine(void *arg)
 {

-       while(1) {      
+       while(1) {

                usleep(sync_frequency_ms * 1000);
                sync();
        }
                usleep(sync_frequency_ms * 1000);
                sync();
        }


@@ -231,10 +355,10 @@ void *calculate_throughput(void *arg)
                size = total_io_size - prev_total_io_size;
                throughput_histogram[throughput_index] = size;
                prev_total_io_size = total_io_size;
                size = total_io_size - prev_total_io_size;
                throughput_histogram[throughput_index] = size;
                prev_total_io_size = total_io_size;

-               throughput_index++;     
+               throughput_index++;

        }
        pthread_exit(NULL);
        }
        pthread_exit(NULL);

-}      
+}

 
 void *io_routine(void *arg)
 {
 
 void *io_routine(void *arg)
 {


@@ -249,7 +373,7 @@ void *io_routine(void *arg)
 
        io_thread_id = (int)arg;
        if (user_specified_file)
 
        io_thread_id = (int)arg;
        if (user_specified_file)

-               strncpy(test_filename, user_fname, MAX_FILENAME);
+               strlcpy(test_filename, user_fname, MAX_FILENAME);

        else
                snprintf(test_filename, MAX_FILENAME, "iosim-%d-%d", (int)getpid(), io_thread_id);
 
        else
                snprintf(test_filename, MAX_FILENAME, "iosim-%d-%d", (int)getpid(), io_thread_id);
 


@@ -261,7 +385,7 @@ void *io_routine(void *arg)
        if (fstat(fd, &filestat) < 0) {
                printf("Error stat()ing file %s!\n", test_filename);
                exit(1);
        if (fstat(fd, &filestat) < 0) {
                printf("Error stat()ing file %s!\n", test_filename);
                exit(1);

-       }       
+       }

 
        if (filestat.st_size < io_size) {
                printf("%s: File size (%lld) smaller than I/O size (%d)!\n", test_filename, filestat.st_size, io_size);
 
        if (filestat.st_size < io_size) {
                printf("%s: File size (%lld) smaller than I/O size (%d)!\n", test_filename, filestat.st_size, io_size);


@@ -272,7 +396,7 @@ void *io_routine(void *arg)
                fcntl(fd, F_NOCACHE, 1);
 
        fcntl(fd, F_RDAHEAD, 0);
                fcntl(fd, F_NOCACHE, 1);
 
        fcntl(fd, F_RDAHEAD, 0);

-       
+

        if(!(data = (char *)calloc(io_size, 1))) {
                perror("Error allocating buffers for I/O!\n");
                exit(1);
        if(!(data = (char *)calloc(io_size, 1))) {
                perror("Error allocating buffers for I/O!\n");
                exit(1);


@@ -280,7 +404,6 @@ void *io_routine(void *arg)
        memset(data, '\0', io_size);
 
        while(1) {
        memset(data, '\0', io_size);
 
        while(1) {

-               

                burst_elapsed = 0;
 
                for(i = 0; i < burst_count; i++) {
                burst_elapsed = 0;
 
                for(i = 0; i < burst_count; i++) {


@@ -290,20 +413,28 @@ void *io_routine(void *arg)
                                        exit(1);
                                }
                        }
                                        exit(1);
                                }
                        }

-                               
+
+                       start_qos_timer();

 
                        gettimeofday(&start_tv, NULL);
                        perform_io(fd, data, io_size, workload_type);
                        gettimeofday(&end_tv, NULL);
 
 
                        gettimeofday(&start_tv, NULL);
                        perform_io(fd, data, io_size, workload_type);
                        gettimeofday(&end_tv, NULL);
 

+                       stop_qos_timer();
+

                        OSAtomicIncrement64(&total_io_count);
                        OSAtomicAdd64(io_size, &total_io_size);
                        elapsed = ((end_tv.tv_sec - start_tv.tv_sec) * 1000000)  + (end_tv.tv_usec - start_tv.tv_usec);
                        OSAtomicIncrement64(&total_io_count);
                        OSAtomicAdd64(io_size, &total_io_size);
                        elapsed = ((end_tv.tv_sec - start_tv.tv_sec) * 1000000)  + (end_tv.tv_usec - start_tv.tv_usec);

+
+                       if (elapsed > max_io_time) {
+                               max_io_time = elapsed;
+                       }
+

                        OSAtomicAdd64(elapsed, &total_io_time);
                        OSAtomicIncrement64(&(latency_histogram[find_io_bin(elapsed, LATENCY_BIN_SIZE, LATENCY_BINS)]));
                        OSAtomicIncrement64(&(low_latency_histogram[find_io_bin(elapsed, LOW_LATENCY_BIN_SIZE, LOW_LATENCY_BINS)]));
                        burst_elapsed += elapsed;
                        OSAtomicAdd64(elapsed, &total_io_time);
                        OSAtomicIncrement64(&(latency_histogram[find_io_bin(elapsed, LATENCY_BIN_SIZE, LATENCY_BINS)]));
                        OSAtomicIncrement64(&(low_latency_histogram[find_io_bin(elapsed, LOW_LATENCY_BIN_SIZE, LOW_LATENCY_BINS)]));
                        burst_elapsed += elapsed;

-                       
+

                        if (inter_io_delay_ms)
                                usleep(inter_io_delay_ms * 1000);
                }
                        if (inter_io_delay_ms)
                                usleep(inter_io_delay_ms * 1000);
                }


@@ -375,7 +506,7 @@ int main(int argc, char *argv[])
        pthread_t throughput_thread;
        char fname[MAX_FILENAME];
 
        pthread_t throughput_thread;
        char fname[MAX_FILENAME];
 

-       while((option = getopt(argc, argv,"hc:i:d:t:f:m:j:s:x:l:z:n:a:")) != -1) {
+       while((option = getopt(argc, argv,"hc:i:d:t:f:m:j:s:x:l:z:n:a:q:")) != -1) {

                switch(option) {
                        case 'c':
                                burst_count = atoi(optarg);
                switch(option) {
                        case 'c':
                                burst_count = atoi(optarg);


@@ -423,7 +554,7 @@ int main(int argc, char *argv[])
                        case 'z':
                                file_size = atoi(optarg);
                                validate_option(file_size, 0, INT_MAX, "File Size", "bytes");
                        case 'z':
                                file_size = atoi(optarg);
                                validate_option(file_size, 0, INT_MAX, "File Size", "bytes");

-                               break; 
+                               break;

                        case 'n':
                                user_fname = optarg;
                                user_specified_file = 1;
                        case 'n':
                                user_fname = optarg;
                                user_specified_file = 1;


@@ -432,6 +563,10 @@ int main(int argc, char *argv[])
                                cached_io_flag = atoi(optarg);
                                validate_option(cached_io_flag, 0, 1, "I/Os cached/no-cached", "");
                                break;
                                cached_io_flag = atoi(optarg);
                                validate_option(cached_io_flag, 0, 1, "I/Os cached/no-cached", "");
                                break;

+                       case 'q':
+                               io_qos_timeout_ms = atoi(optarg);
+                               validate_option(io_qos_timeout_ms, 0, INT_MAX, "I/O QoS timeout", "msecs");
+                               break;

                        default:
                                printf("Unknown option %c\n", option);
                                print_usage();
                        default:
                                printf("Unknown option %c\n", option);
                                print_usage();


@@ -452,26 +587,29 @@ int main(int argc, char *argv[])
        print_test_setup(test_duration, "Test duration", "secs", "0 indicates tool waits for Ctrl+C");
        print_test_setup(io_tier, "I/O Tier", "", 0);
        print_test_setup(cached_io_flag, "I/O Caching", "", "0 indicates non-cached I/Os");
        print_test_setup(test_duration, "Test duration", "secs", "0 indicates tool waits for Ctrl+C");
        print_test_setup(io_tier, "I/O Tier", "", 0);
        print_test_setup(cached_io_flag, "I/O Caching", "", "0 indicates non-cached I/Os");

+       print_test_setup(io_qos_timeout_ms, "I/O QoS Threshold Timeout", "msecs", 0);

        print_test_setup(0, "File read-aheads", "", "0 indicates read-aheads disabled");
        print_test_setup(0, "File read-aheads", "", "0 indicates read-aheads disabled");

-       
+

        printf("**********************************************************\n");
 
        if (user_specified_file == 0) {
                char dd_command[MAX_CMD_SIZE];
                for (i=0; i < thread_count; i++) {
                        snprintf(fname, MAX_FILENAME, "iosim-%d-%d", (int)getpid(), i);
        printf("**********************************************************\n");
 
        if (user_specified_file == 0) {
                char dd_command[MAX_CMD_SIZE];
                for (i=0; i < thread_count; i++) {
                        snprintf(fname, MAX_FILENAME, "iosim-%d-%d", (int)getpid(), i);

-                       snprintf(dd_command, MAX_CMD_SIZE, "dd if=/dev/urandom of=%s bs=4096 count=%d", fname, file_size);  
+                       snprintf(dd_command, MAX_CMD_SIZE, "dd if=/dev/urandom of=%s bs=4096 count=%d", fname, file_size);

                        printf("Creating file %s of size %lld...\n", fname, ((int64_t)file_size * 4096));
                        printf("Creating file %s of size %lld...\n", fname, ((int64_t)file_size * 4096));

-                       system(dd_command);
+                       system_cmd(dd_command);

                }
        } else {
                printf("Using user specified file %s for all threads...\n", user_fname);
        }
                }
        } else {
                printf("Using user specified file %s for all threads...\n", user_fname);
        }

-       system("purge");
+       system_cmd("purge");

        setup_process_io_policy(io_tier);
 
        setup_process_io_policy(io_tier);
 

-       printf("**********************************************************\n");         
-       printf("Creating threads and generating workload...\n");        
+       setup_qos_device();
+
+       printf("**********************************************************\n");
+       printf("Creating threads and generating workload...\n");

 
        signal(SIGINT, signalHandler);
        signal(SIGALRM, signalHandler);
 
        signal(SIGINT, signalHandler);
        signal(SIGALRM, signalHandler);


@@ -495,18 +633,41 @@ int main(int argc, char *argv[])
                exit(1);
        }
 
                exit(1);
        }
 

-       /* All threads are now initialized */
-       if (test_duration)
-               alarm(test_duration);   
+       if(io_qos_timeout_ms > 0) {
+               CFRunLoopRunInMode(kCFRunLoopDefaultMode, (CFTimeInterval)test_duration, false);
+               alarm(1);
+       } else {
+               /* All threads are now initialized */
+               if (test_duration)
+                       alarm(test_duration);
+       }

 
        for(i=0; i < thread_count; i++)
                pthread_join(thread_list[i], NULL);
 
        for(i=0; i < thread_count; i++)
                pthread_join(thread_list[i], NULL);

-       
+

        if (sync_frequency_ms)
                pthread_join(sync_thread, NULL);
 
        pthread_join(throughput_thread, NULL);
 
        pthread_exit(0);
        if (sync_frequency_ms)
                pthread_join(sync_thread, NULL);
 
        pthread_join(throughput_thread, NULL);
 
        pthread_exit(0);

+}
+
+extern char **environ;

 
 

+int system_cmd(char *command)
+{
+    // workaround for rdar://problem/53281655
+    pid_t pid;
+    char *argv[] = {"sh", "-c", command, NULL};
+    int status;
+    status = posix_spawn(&pid, "/bin/sh", NULL, NULL, argv, environ);
+    if (status == 0) {
+        if (waitpid(pid, &status, 0) != -1) {
+            return status;
+        } else {
+            perror("waitpid");
+        }
+    }
+    return -1;

 }
 }