COMP 3000 Lab 4 2011 - Revision history

Afry at 18:51, 10 November 2011

2011-11-10T18:51:44Z

← Older revision		Revision as of 18:51, 10 November 2011
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	# The program outputs the results of the two threads producer and consumer. For the first half of rounds on the lab computers which have two processors, the consumer won, followed by the producer for the second half. On my netbook the consumer won the first twelve under a high load, the first 18 on a medium load, then the first 18 plus 10 in the middle on light load. Load does have an effect on the output as shown by my experiment. The reason why is because although threads are created with much less operating system overhead, they still share the same address space within the process in which they are created. /ref{https://computing.llnl.gov/tutorials/pthreads/ (bad ssl cert, but good infoz)}		# The program outputs the results of the two threads producer and consumer. For the first half of rounds on the lab computers which have two processors, the consumer won, followed by the producer for the second half. On my netbook the consumer won the first twelve under a high load, the first 18 on a medium load, then the first 18 plus 10 in the middle on light load. Load does have an effect on the output as shown by my experiment. The reason why is because although threads are created with much less operating system overhead, they still share the same address space within the process in which they are created. /ref{https://computing.llnl.gov/tutorials/pthreads/ (bad ssl cert, but good infoz)}
	# The version number is: 2.11.1-0ubuntu7 and this was shown by either of these three commands: * apt-cache show libc6 * dpkg -l \| grep libc6 * /lib/libc.so.6 **(the ldd -version command can give you the information of which library was used to compile ldd on the system, this may not correspond to the correct glibc version)		# The version number is: 2.11.1-0ubuntu7 and this was shown by either of these three commands: * apt-cache show libc6 * dpkg -l \| grep libc6 * /lib/libc.so.6 ** Special Note: (the ldd -version command can give you the information of which library was used to compile ldd on the system, this may not correspond to the correct glibc version)
	# The /etc/init.d folder contains a number of start / stop scripts for various services on your system. The /etc/init.d/ssh file is a script (denoted by #! /bin/sh at the beginning of the file) that is used to start and stop the OpenBSD secure shell daemon. It tests the sshd daemon executable for the correct permissions and that the file exists. This script also tests if this is to be run in a chrooted environment, if this script was invoked by init, and whether the service actually started. Upon starting and stopping this script also logs messages regarding stopping and starting of the service utilizing log_daemon_msg. /ref{man page}		# The /etc/init.d folder contains a number of start / stop scripts for various services on your system. The /etc/init.d/ssh file is a script (denoted by #! /bin/sh at the beginning of the file) that is used to start and stop the OpenBSD secure shell daemon. It tests the sshd daemon executable for the correct permissions and that the file exists. This script also tests if this is to be run in a chrooted environment, if this script was invoked by init, and whether the service actually started. Upon starting and stopping this script also logs messages regarding stopping and starting of the service utilizing log_daemon_msg. /ref{man page}
	# The /etc/init folder contains all of the configuration files for various scripts that are run by init. Init is a program that spawns all other processes on a Unix-based operating system. The program runs as a daemon and usually has the process id of 1. A daemon is a computer program that runs as a background process rather than being in direct control of an interactive user. /ref{http://en.wikipedia.org/wiki/Daemon_%28computer_software%29) /etc/init/cron.conf is the configuration file which includes a description of cron, specifies the runlevel of cron, declares potential forks and execs cron itself.		# The /etc/init folder contains all of the configuration files for various scripts that are run by init. Init is a program that spawns all other processes on a Unix-based operating system. The program runs as a daemon and usually has the process id of 1. A daemon is a computer program that runs as a background process rather than being in direct control of an interactive user. /ref{http://en.wikipedia.org/wiki/Daemon_%28computer_software%29) /etc/init/cron.conf is the configuration file which includes a description of cron, specifies the runlevel of cron, declares potential forks and execs cron itself.

Afry at 18:51, 10 November 2011

2011-11-10T18:51:20Z

← Older revision		Revision as of 18:51, 10 November 2011
Line 115:		Line 115:

	# The program outputs the results of the two threads producer and consumer. For the first half of rounds on the lab computers which have two processors, the consumer won, followed by the producer for the second half. On my netbook the consumer won the first twelve under a high load, the first 18 on a medium load, then the first 18 plus 10 in the middle on light load. Load does have an effect on the output as shown by my experiment. The reason why is because although threads are created with much less operating system overhead, they still share the same address space within the process in which they are created. /ref{https://computing.llnl.gov/tutorials/pthreads/ (bad ssl cert, but good infoz)}		# The program outputs the results of the two threads producer and consumer. For the first half of rounds on the lab computers which have two processors, the consumer won, followed by the producer for the second half. On my netbook the consumer won the first twelve under a high load, the first 18 on a medium load, then the first 18 plus 10 in the middle on light load. Load does have an effect on the output as shown by my experiment. The reason why is because although threads are created with much less operating system overhead, they still share the same address space within the process in which they are created. /ref{https://computing.llnl.gov/tutorials/pthreads/ (bad ssl cert, but good infoz)}
	# The version number is: 2.11.1-0ubuntu7 and this was shown by either of these ~~two~~ commands: * apt-cache show libc6 * dpkg -l \| grep libc6		# The version number is: 2.11.1-0ubuntu7 and this was shown by either of these three commands: * apt-cache show libc6 * dpkg -l \| grep libc6 * /lib/libc.so.6 **(the ldd -version command can give you the information of which library was used to compile ldd on the system, this may not correspond to the correct glibc version)
	# The /etc/init.d folder contains a number of start / stop scripts for various services on your system. The /etc/init.d/ssh file is a script (denoted by #! /bin/sh at the beginning of the file) that is used to start and stop the OpenBSD secure shell daemon. It tests the sshd daemon executable for the correct permissions and that the file exists. This script also tests if this is to be run in a chrooted environment, if this script was invoked by init, and whether the service actually started. Upon starting and stopping this script also logs messages regarding stopping and starting of the service utilizing log_daemon_msg. /ref{man page}		# The /etc/init.d folder contains a number of start / stop scripts for various services on your system. The /etc/init.d/ssh file is a script (denoted by #! /bin/sh at the beginning of the file) that is used to start and stop the OpenBSD secure shell daemon. It tests the sshd daemon executable for the correct permissions and that the file exists. This script also tests if this is to be run in a chrooted environment, if this script was invoked by init, and whether the service actually started. Upon starting and stopping this script also logs messages regarding stopping and starting of the service utilizing log_daemon_msg. /ref{man page}
	# The /etc/init folder contains all of the configuration files for various scripts that are run by init. Init is a program that spawns all other processes on a Unix-based operating system. The program runs as a daemon and usually has the process id of 1. A daemon is a computer program that runs as a background process rather than being in direct control of an interactive user. /ref{http://en.wikipedia.org/wiki/Daemon_%28computer_software%29) /etc/init/cron.conf is the configuration file which includes a description of cron, specifies the runlevel of cron, declares potential forks and execs cron itself.		# The /etc/init folder contains all of the configuration files for various scripts that are run by init. Init is a program that spawns all other processes on a Unix-based operating system. The program runs as a daemon and usually has the process id of 1. A daemon is a computer program that runs as a background process rather than being in direct control of an interactive user. /ref{http://en.wikipedia.org/wiki/Daemon_%28computer_software%29) /etc/init/cron.conf is the configuration file which includes a description of cron, specifies the runlevel of cron, declares potential forks and execs cron itself.

Afry: Added marks

2011-11-10T16:32:26Z

Added marks

← Older revision		Revision as of 16:32, 10 November 2011
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	==Part A==		==Part A==

	# Compile and run ''race-demo.c''. What does the program output? Describe the pattern. Does the output vary depending upon the system load?		# Compile and run ''race-demo.c''. What does the program output? Describe the pattern. Does the output vary depending upon the system load? (2 marks)
	# What version of the glibc library is installed on the SCS lambda machines? What command did you use to figure this out?		# What version of the glibc library is installed on the SCS lambda machines? What command did you use to figure this out? (2 marks)
	# What does the file /etc/init.d/ssh do on the lambda machines?		# What does the file /etc/init.d/ssh do on the lambda machines? (1 mark)
	# What does the file /etc/init/cron.conf do on the lambda machines?		# What does the file /etc/init/cron.conf do on the lambda machines? (1 mark)
	# What does the file /etc/init.d/cron do on the lambda machines?		# What does the file /etc/init.d/cron do on the lambda machines? (1 mark)

	==Part B==		==Part B==

	# Modify ''race-demo.c'' to create '''rigged-race.c''', a program that is identical in behavior to race-demo.c except that the consumer always wins X races while the producer wins ROUNDS-X races. Synchronize the two threads using the '''pthread_mutex''' functions (init, lock, unlock, trylock).		# Modify ''race-demo.c'' to create '''rigged-race.c''', a program that is identical in behavior to race-demo.c except that the consumer always wins X races while the producer wins ROUNDS-X races. Synchronize the two threads using the '''pthread_mutex''' functions (init, lock, unlock, trylock). (1 mark)
	# Modify ''race-demo.c'' to create '''p-c.c''', a program based on race-demo where the producer only increments values in the buffer by one while the consumer only decrements the buffer values by one. Arrange it, however, such that the values in the buffer are always 0 or 1. If the consumer will decrement a 0, it should go to sleep until the producer wakes it up. Similarly, the producer should go to sleep if it finds it will increment a 1, with the consumer waking the producer at the appropriate time.		# Modify ''race-demo.c'' to create '''p-c.c''', a program based on race-demo where the producer only increments values in the buffer by one while the consumer only decrements the buffer values by one. Arrange it, however, such that the values in the buffer are always 0 or 1. If the consumer will decrement a 0, it should go to sleep until the producer wakes it up. Similarly, the producer should go to sleep if it finds it will increment a 1, with the consumer waking the producer at the appropriate time. (1 mark)
	# UNIX System V init has a simple system for initializing system services by running a set of shell scripts at different "run levels." Why aren't collections of shell scripts considered sufficient for initializing modern UNIX-like systems such as MacOS X and Ubuntu?		# UNIX System V init has a simple system for initializing system services by running a set of shell scripts at different "run levels." Why aren't collections of shell scripts considered sufficient for initializing modern UNIX-like systems such as MacOS X and Ubuntu? (1 mark)

	==Programs==		==Programs==

Afry at 15:28, 10 November 2011

2011-11-10T15:28:53Z

← Older revision		Revision as of 15:28, 10 November 2011
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	== Part B ==		== Part B ==
			#
			#
			# Since the init shell scripts are run sequentially, this does not take advantage of parallel processing capabilities of multi core machines. ''Launchd'' and ''Upstart'' both enable multiple processes to run simultaneously, speeding up boot times.

Afry at 19:47, 7 November 2011

2011-11-07T19:47:56Z

← Older revision		Revision as of 19:47, 7 November 2011
Line 121:		Line 121:

	== Part B ==		== Part B ==
	~~/* rigged-race.c */~~

	~~/* compile with -pthread flag, e.g.~~
	~~gcc -pthread race-demo.c -o rigged-race */~~

	~~#include <stdlib.h>~~
	~~#include <stdio.h>~~
	~~#include <pthread.h>~~

	~~int value;~~
	~~int offset = -1;~~

	~~#define SIZE 10000~~
	~~#define ROUNDS 100~~
	~~#define GAME 30~~
	~~pthread_mutex_t mutex;~~
	~~pthread_cond_t x_thresh;~~
	~~pthread_cond_t y_thresh;~~

	~~void consume_func(void arg) {~~
	~~int i,r;~~
	~~int *buffer;~~
	~~buffer = (int *) arg;~~
	~~for (r = 1; r <= ROUNDS; r++) {~~
	~~sleep(1);~~
	~~pthread_mutex_lock(&mutex);~~
	~~if (r > GAME){~~
	~~pthread_cond_wait(&x_thresh,&mutex);~~
	~~printf("Consumer waiting");~~
	}
	~~for (i = 0; i < SIZE; i++) {~~
	~~if (buffer[i] < r ) {~~
	~~buffer[i] = -1;~~
	}
	}
	~~pthread_cond_signal(&y_thresh);~~
	~~pthread_mutex_unlock(&mutex);~~
	}
	~~return NULL;~~
	}

	~~void produce_func( void arg ) {~~
	~~int i, r, iwon;~~
	~~int *buffer;~~
	~~buffer = (int *) arg;~~
	~~for (r = 1; r <= ROUNDS; r++) {~~
	~~pthread_mutex_lock(&mutex);~~
	~~if (r <= GAME){~~
	~~pthread_cond_wait(&y_thresh,&mutex);~~
	~~printf("producer waiting");~~
	}
	~~iwon = 1;~~
	~~for( i = 0; i < SIZE; i++ ) {~~
	~~if (buffer[i] == r-1) {~~
	~~buffer[i] = r;~~
	~~} else if ((buffer[i] < r) && (buffer[i] != -1)) {~~
	~~fprintf(stderr,~~
	~~"Huh?! Got value %d\n",~~
	~~(int) buffer[i]);~~
	~~exit(-1);~~
	~~} else if (buffer[i] == -1) {~~
	~~if (iwon) {~~
	~~printf("Consumer got to %d first on round %d.\n", i,r);~~
	~~iwon = 0;~~
	}
	~~buffer[i] = r;~~
	}
	}

	~~if (iwon) {~~
	~~printf("Producer won on round %d!\n",r);~~
	~~} else {~~
	~~printf("Producer lost on round %d.\n",r);~~
	}
	~~pthread_cond_signal(&x_thresh);~~
	~~pthread_mutex_unlock(&mutex);~~
	}
	~~return NULL;~~
	}

	~~int main(int argc, char *argv[]) {~~
	~~int *buffer;~~
	~~pthread_t producer_thread, consumer_thread;~~
	~~pthread_mutex_init(&mutex,NULL);~~
	~~pthread_cond_init(&x_thresh,NULL);~~
	~~pthread_cond_init(&y_thresh,NULL);~~
	~~int r1, r2;~~

	~~buffer = (int *) calloc(SIZE, sizeof(int));~~

	~~if (buffer == NULL) {~~
	~~fprintf(stderr, "Couldn't allocate memory for buffer!");~~
	~~exit(-1);~~
	}

	~~r1 = pthread_create(&producer_thread, NULL, produce_func, buffer);~~
	~~r2 = pthread_create(&consumer_thread, NULL, consume_func, buffer);~~

	~~if (r1 != 0 \|\| r2 != 0) {~~
	~~fprintf(stderr, "Couldn't create threads.\n");~~
	}

	~~pthread_join(producer_thread, NULL);~~
	~~pthread_join(consumer_thread, NULL);~~

	~~return 0;~~
	}

Afry at 19:45, 7 November 2011

2011-11-07T19:45:14Z

← Older revision		Revision as of 19:45, 7 November 2011
Line 121:		Line 121:

	== Part B ==		== Part B ==
	/* rigged-race.c */		/* rigged-race.c */

	/* compile with -pthread flag, e.g.		/* compile with -pthread flag, e.g.
	gcc -pthread race-demo.c -o rigged-race */		gcc -pthread race-demo.c -o rigged-race */

	#include <stdlib.h>		#include <stdlib.h>
	#include <stdio.h>		#include <stdio.h>
	#include <pthread.h>		#include <pthread.h>

	int value;		int value;
	int offset = -1;		int offset = -1;

	#define SIZE 10000		#define SIZE 10000
	#define ROUNDS 100		#define ROUNDS 100
	#define GAME 30		#define GAME 30
	pthread_mutex_t mutex;		pthread_mutex_t mutex;
	pthread_cond_t x_thresh;		pthread_cond_t x_thresh;
	pthread_cond_t y_thresh;		pthread_cond_t y_thresh;

	void consume_func(void arg) {		void consume_func(void arg) {
	int i,r;		int i,r;
	int *buffer;		int *buffer;
	buffer = (int *) arg;		buffer = (int *) arg;
	for (r = 1; r <= ROUNDS; r++) {		for (r = 1; r <= ROUNDS; r++) {
	sleep(1);		sleep(1);
	pthread_mutex_lock(&mutex);		pthread_mutex_lock(&mutex);
	if (r > GAME){		if (r > GAME){
Line 160:		Line 160:
	}		}
	return NULL;		return NULL;
	}		}

	void produce_func( void arg ) {		void produce_func( void arg ) {
	int i, r, iwon;		int i, r, iwon;
	int *buffer;		int *buffer;
Line 199:		Line 199:
	}		}
	return NULL;		return NULL;
	}		}

	int main(int argc, char *argv[]) {		int main(int argc, char *argv[]) {
	int *buffer;		int *buffer;
	pthread_t producer_thread, consumer_thread;		pthread_t producer_thread, consumer_thread;
Line 227:		Line 227:

	return 0;		return 0;
	}		}

Afry at 19:42, 7 November 2011

2011-11-07T19:42:44Z

← Older revision		Revision as of 19:42, 7 November 2011
Line 119:		Line 119:
	# The /etc/init folder contains all of the configuration files for various scripts that are run by init. Init is a program that spawns all other processes on a Unix-based operating system. The program runs as a daemon and usually has the process id of 1. A daemon is a computer program that runs as a background process rather than being in direct control of an interactive user. /ref{http://en.wikipedia.org/wiki/Daemon_%28computer_software%29) /etc/init/cron.conf is the configuration file which includes a description of cron, specifies the runlevel of cron, declares potential forks and execs cron itself.		# The /etc/init folder contains all of the configuration files for various scripts that are run by init. Init is a program that spawns all other processes on a Unix-based operating system. The program runs as a daemon and usually has the process id of 1. A daemon is a computer program that runs as a background process rather than being in direct control of an interactive user. /ref{http://en.wikipedia.org/wiki/Daemon_%28computer_software%29) /etc/init/cron.conf is the configuration file which includes a description of cron, specifies the runlevel of cron, declares potential forks and execs cron itself.
	# The /etc/init.d/cron file is associated with the cron daemon which is a time-based job scheduler. The file also creates a symbolic link target for init scripts that have been converted to Upstart.		# The /etc/init.d/cron file is associated with the cron daemon which is a time-based job scheduler. The file also creates a symbolic link target for init scripts that have been converted to Upstart.

	== Part B ==		== Part B ==
	#/* rigged-race.c */		/* rigged-race.c */

	/* compile with -pthread flag, e.g.		/* compile with -pthread flag, e.g.
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	return 0;		return 0;
	}		}
	#
	#

Afry at 19:41, 7 November 2011

2011-11-07T19:41:47Z

@@ Line 120: / Line 120: @@
 # The /etc/init.d/cron file is associated with the cron daemon which is a time-based job scheduler. The file also creates a symbolic link target for init scripts that have been converted to Upstart.
 == Part B ==
+#/* rigged-race.c */
+#
+#

Afry at 05:25, 7 November 2011

2011-11-07T05:25:00Z

← Older revision		Revision as of 05:25, 7 November 2011
Line 118:		Line 118:
	# The /etc/init.d folder contains a number of start / stop scripts for various services on your system. The /etc/init.d/ssh file is a script (denoted by #! /bin/sh at the beginning of the file) that is used to start and stop the OpenBSD secure shell daemon. It tests the sshd daemon executable for the correct permissions and that the file exists. This script also tests if this is to be run in a chrooted environment, if this script was invoked by init, and whether the service actually started. Upon starting and stopping this script also logs messages regarding stopping and starting of the service utilizing log_daemon_msg. /ref{man page}		# The /etc/init.d folder contains a number of start / stop scripts for various services on your system. The /etc/init.d/ssh file is a script (denoted by #! /bin/sh at the beginning of the file) that is used to start and stop the OpenBSD secure shell daemon. It tests the sshd daemon executable for the correct permissions and that the file exists. This script also tests if this is to be run in a chrooted environment, if this script was invoked by init, and whether the service actually started. Upon starting and stopping this script also logs messages regarding stopping and starting of the service utilizing log_daemon_msg. /ref{man page}
	# The /etc/init folder contains all of the configuration files for various scripts that are run by init. Init is a program that spawns all other processes on a Unix-based operating system. The program runs as a daemon and usually has the process id of 1. A daemon is a computer program that runs as a background process rather than being in direct control of an interactive user. /ref{http://en.wikipedia.org/wiki/Daemon_%28computer_software%29) /etc/init/cron.conf is the configuration file which includes a description of cron, specifies the runlevel of cron, declares potential forks and execs cron itself.		# The /etc/init folder contains all of the configuration files for various scripts that are run by init. Init is a program that spawns all other processes on a Unix-based operating system. The program runs as a daemon and usually has the process id of 1. A daemon is a computer program that runs as a background process rather than being in direct control of an interactive user. /ref{http://en.wikipedia.org/wiki/Daemon_%28computer_software%29) /etc/init/cron.conf is the configuration file which includes a description of cron, specifies the runlevel of cron, declares potential forks and execs cron itself.
			# The /etc/init.d/cron file is associated with the cron daemon which is a time-based job scheduler. The file also creates a symbolic link target for init scripts that have been converted to Upstart.
	== Part B ==		== Part B ==
			#
			#
			#

Afry at 05:14, 7 November 2011

2011-11-07T05:14:27Z

← Older revision		Revision as of 05:14, 7 November 2011
Line 115:		Line 115:

	# The program outputs the results of the two threads producer and consumer. For the first half of rounds on the lab computers which have two processors, the consumer won, followed by the producer for the second half. On my netbook the consumer won the first twelve under a high load, the first 18 on a medium load, then the first 18 plus 10 in the middle on light load. Load does have an effect on the output as shown by my experiment. The reason why is because although threads are created with much less operating system overhead, they still share the same address space within the process in which they are created. /ref{https://computing.llnl.gov/tutorials/pthreads/ (bad ssl cert, but good infoz)}		# The program outputs the results of the two threads producer and consumer. For the first half of rounds on the lab computers which have two processors, the consumer won, followed by the producer for the second half. On my netbook the consumer won the first twelve under a high load, the first 18 on a medium load, then the first 18 plus 10 in the middle on light load. Load does have an effect on the output as shown by my experiment. The reason why is because although threads are created with much less operating system overhead, they still share the same address space within the process in which they are created. /ref{https://computing.llnl.gov/tutorials/pthreads/ (bad ssl cert, but good infoz)}
	# The version number is: 2.11.1-0ubuntu7 and this was shown by either of these two commands:		# The version number is: 2.11.1-0ubuntu7 and this was shown by either of these two commands: * apt-cache show libc6 * dpkg -l \| grep libc6
	* apt-cache show libc6
	* dpkg -l \| grep libc6
	# The /etc/init.d folder contains a number of start / stop scripts for various services on your system. The /etc/init.d/ssh file is a script (denoted by #! /bin/sh at the beginning of the file) that is used to start and stop the OpenBSD secure shell daemon. It tests the sshd daemon executable for the correct permissions and that the file exists. This script also tests if this is to be run in a chrooted environment, if this script was invoked by init, and whether the service actually started. Upon starting and stopping this script also logs messages regarding stopping and starting of the service utilizing log_daemon_msg. /ref{man page}		# The /etc/init.d folder contains a number of start / stop scripts for various services on your system. The /etc/init.d/ssh file is a script (denoted by #! /bin/sh at the beginning of the file) that is used to start and stop the OpenBSD secure shell daemon. It tests the sshd daemon executable for the correct permissions and that the file exists. This script also tests if this is to be run in a chrooted environment, if this script was invoked by init, and whether the service actually started. Upon starting and stopping this script also logs messages regarding stopping and starting of the service utilizing log_daemon_msg. /ref{man page}
	# The /etc/init folder contains all of the configuration files for various scripts that are run by init.		# The /etc/init folder contains all of the configuration files for various scripts that are run by init. Init is a program that spawns all other processes on a Unix-based operating system. The program runs as a daemon and usually has the process id of 1. A daemon is a computer program that runs as a background process rather than being in direct control of an interactive user. /ref{http://en.wikipedia.org/wiki/Daemon_%28computer_software%29) /etc/init/cron.conf is the configuration file which includes a description of cron, specifies the runlevel of cron, declares potential forks and execs cron itself.

	== Part B ==		== Part B ==