- Amazon Prime Video offers access to thousands of titles for $8.99 a month as a standalone subscription. A full Prime membership, however, will cost you only $12.99 a month (or the discounted rate of $120 for a full year), and grant you access to Prime Video as well as discounts on certain items and free two-day shipping.
- Jan 30, 2021 Although it started as a Mac OS X exclusive at launch, Unity now includes use through Windows, macOS, and Linux. The user can choose to build projects using 3D or 2D worlds, assets, and more. The user can choose to build projects using 3D or 2D worlds, assets, and more.
- The mini had an 80 GB hard drive, which I saved and laid aside so, when in trouble, I could go back to the original OS X Lion. I build in a 120 GB drive, but I didn't manage to get it working with Yosemite. I attached a 160GB drive to the mac and I managed to get it installed with Yosemite. I also upgraded it to 10.10.5.
- Showdown - Gam 120 Final Project Mac Os Catalina
- Showdown - Gam 120 Final Project Mac Os Download
- Showdown - Gam 120 Final Project Mac Os X
Table of Contents
Aug 17, 2020 Command Line Tools installation was removed (on 11.0 only) because Apple were regularly having issues offering the latest version through xcode-select -install.At the time of removal, it was offering an older version on x8664 (which was very bad because it had the 10.16 SDK while the OS was 11.0, which breaks many things) and it was downloading a version on Apple Silicon that only worked on.
- Installation using the self-extracting archive (osx_x64_64_sfx.exe)
To install GAMS, please follow the steps below as closely as possible. We advise you to read this entire document before beginning the installation procedure. Furthermore, we recommend to use the PKG installer for Mac OS X because it includes the GAMS Studio and it integrates GAMS into Mac OS X, e.g. it is possible to open the GAMS Studio via the Launchpad.
Two installation procedures are available for GAMS on Mac OS X:
- Obtain the GAMS PKG file, which is available from http://www.gams.com/download.
- Double click the package and follow the instructions. By clicking on
Customise
in the tabInstallation Type
you can decide to add GAMS to the PATH as well as to reject the installation of GAMS Studio. Note that adding GAMS to the PATH is done by modifying your shell profile file (~/.zprofile
,~/.bash_profile
etc.). A backup of your old profile is saved (~/.zprofile.gamsbackup
,~/.bash_profile.gamsbackup
etc.). - In order to test the GAMS installation with
GAMS Studio
open theLaunchpad
and click theGAMS Studio 34
icon to open the application. Alternatively, go to Applications and open theGAMS Studio 34
application. Install your license via the corresponding GAMS Studio dialog. The license file is nowadays sent via email, with instructions. You can also request a demo license from http://www.gams.com/download.
Optionally, you can create the license file 'gamslice.txt' in a directory that GAMS searches to find a license. GAMS searches a couple of system wide and user specific standard locations for a license file.
- Open the
Model Library Explorer
and open theTRNSPORT
model (sequence number 001). Run the model and check the contents of the process log, which should be similar to the Terminal output listed in the next bullet point. In order to test the GAMS installation without using
GAMS Studio
open a Terminal window. Execute the following commands to see if everything works as expected:The output should be similar to this:
Showdown - Gam 120 Final Project Mac Os Catalina
To uninstall a GAMS installation that was installed using the PKG installer, run the following command from the terminal: sudo bash /Library/Frameworks/GAMS.framework/Versions/34/Resources/uninstall.sh
. Additionally, you can remove GAMS from the PATH in your shell profile file (~/.zprofile
, ~/.bash_profile
) if GAMS was added to the PATH during installation.
- Obtain the GAMS distribution file, which is available from http://www.gams.com/download, in one large self-extracting zip archive with a
_sfx.exe
file extension, e.g.,osx_x64_64_sfx.exe
. Check that it has the execute permission set. If you are not sure how to do this, just type in the commandchmod 755 osx_x64_64_sfx.exe
.- Attention
- The common way to install GAMS on a Mac is the PKG installer. When one tries to run the sfx installer (e.g. for unattended installation) under macOS 10.15 (Catalina) or newer, the installer and several related files will be tagged with the
com.apple.quarantine
flag. There are different solutions to this problem:- The flag can be removed by the following command:
- Instead of downloading the sfx installer through the browser, use a command line tool such as curl (note that by downloading the software, you agree to the License Agreement). The download link may need to be adjusted, depending on the distribution that should be downloaded.
- Choose a location where you want to create the GAMS system directory (the GAMS system directory is the directory where the GAMS system files should reside). At this location the GAMS installer will create a subdirectory with a name that indicates the distribution of GAMS you are installing. For example, if you are installing the 24.3 distribution in
/Applications/GAMS
, the installer will create the GAMS system directory/Applications/GAMS/gams24.3_osx_x64_64_sfx
. If the directory where you want to install GAMS is not below your home directory, you may need to have root privileges on the machine. - Create the directory that should contain the GAMS system directory, for instance
/Applications/GAMS
. Change to this directory (cd /Applications/GAMS
). Make surepwd
returns the name of this directory correctly. - Run the distribution file, either from its current location or after transfering it to the directory that should contain the GAMS system directory. By executing the distribution file, the GAMS distribution should be extracted. For example, if you downloaded the distribution file into your home directory, you might execute the following commands:
Create the license file
gamslice.txt
in a directory GAMS searches to find a license. The license file is nowadays sent via email, with instructions. You can also request a demo license from http://www.gams.com/download.- Attention
- Do not store the
gamslice.txt
in the GAMS system directory. This invalidates the code signature and cause Gatekeeper to reject the bundle!
GAMS searches a couple of system wide and user specific locations for a license file. For Mac OS X these locations include
/Library/Application Support/GAMS
and/Users/username/Library/Application Support/GAMS
. The locations can vary due to different system configuration. One can get an ordered list of data directories GAMS searches forgamslice.txt
by running the program./gamsinst -listdirs
from the GAMS system directory. Even though this list might contain locations in the system directory, e.g./Applications/GAMS31.1
we strongly discourage to placegamslice.txt
here.Change to the GAMS system directory and run the program
./gamsinst
. It will prompt you for default solvers to be used for each class of models. If possible, choose solvers you have licensed since unlicensed solvers will only run in demonstration mode. These solver defaults can be changed or overridden by:a. rerunning
./gamsinst
and resetting the default valuesb. setting a command line default, e.g.,
gams trnsport lp=soplex
c. an option statement in the GAMS model, e.g:
option lp=soplex;
- Add the GAMS system directory to your path (see below).
- To test the installation, log in as a normal user and run a few models from your home directory, but not the GAMS system directory:
- If you move the GAMS system to another directory, remember to rerun
./gamsinst
. It is also good practice to rerun./gamsinst
when you change your license file if this has changed the set of licensed solvers.
Access to GAMS
To run GAMS you must be able to execute the GAMS programs located in the GAMS system directory. There are several ways to do this. Remember that the GAMS system directory in the examples below may not correspond to the directory where you have installed your GAMS system.
- If you are using the C shell (
csh
) and its variants you can modify your.cshrc
file by adding the second of the two lines given below: - Those of you using the Bourne (
sh
) or Korn (ksh
) shells and their variants can modify their.profile
file by adding the second of the three lines below: If the.profile
file does not exist yet, it needs to be created. You should log out and log in again after you have made any changes to your path. - You may prefer to use an alias for the names of the programs instead of modifying the path as described above. C shell users can use the following commands on the command line or in their
.cshrc
file: The correct Bourne or Korn shell syntax (either command line or.profile
) is: Again, you should log out and log in in order to put the alias settings in.cshrc
or.profile
into effect. - Casual users can always type the absolute path names of the GAMS programs, e.g.:
Example
The following shows the log of a session, where a user downloads a GAMS 24.3.1 system and installs it under Applications/GAMS/gams24.3_osx_x64_64_sfx
. It is assumed that a GAMS license file has been stored as /Users/doe/gamslice.txt
.
Showdown - Gam 120 Final Project Mac Os Download
Winter 2020
Deadlines
Draft of Intro, Machine Description, and CPU Operations: | Tuesday, February 4 at 8am (start of class) |
Draft of Memory Operations: | |
Final report with all measurements plus code: | Thursday, March 12 at 8am (start of class) |
Overview
In building an operating system, it is important to be able todetermine the performance characteristics of underlying hardwarecomponents (CPU, RAM, disk, network, etc.), and to understand howtheir performance influences or constrains operating system services.Likewise, in building an application, one should understand theperformance of the underlying hardware and operating system, and howthey relate to the user's subjective sense of that application's'responsiveness'. While some of the relevant quantities can be foundin specs and documentation, many must be determined experimentally.While some values may be used to predict others, the relations betweenlower-level and higher-level performance are often subtle andnon-obvious.
In this project, you will create, justify, and apply a set ofexperiments to a system to characterize and understand itsperformance. In addition, you may explore the relations between someof these quantities. In doing so, you will study how to usebenchmarks to usefully characterize a complex system. You should alsogain an intuitive feel for the relative speeds of different basicoperations, which is invaluable in identifying performance bottlenecks.
You have complete choice over the operation system and hardwareplatform for your measurements. You can use your laptop that you arecomfortable with, an operating system running in a virtual machinemonitor, a smartphone, a game system, or even a supercomputer.
You may work either alone or in 2–3 person groups. Groupsdo the same project as individuals. All members receive the samegrade. Note that working in groups may or may not make the projecteasier, depending on how the group interactions work out. Ifcollaboration issues arise, contact your instructor as soon aspossible: flexibility in dealing with such issues decreases as thedeadline approaches.
This project has two parts. First, you will implement and performa series of experiments. Second, you will write a report documentingthe methodology and results of your experiments. When you finish, youwill submit your report as well as the code used to perform yourexperiments.
Report
Showdown - Gam 120 Final Project Mac Os X
Your report will have a number of sections including anintroduction, a machine description, and descriptions and discussionsof your experiments.
1) Introduction
Describe the goals of the project and, if you are in a group, whoperformed which experiments. State the language you used to implementyour measurements, and the compiler version and optimization settingsyou used to compile your code. If you are measuring in an unusualenvironment (e.g., virtual machine, Web browser, compute cloud, etc.),discuss the implications of the environment on the measurement task(e.g., additional variance that is difficult for you to control for).Estimate the amount of time you spent on this project.2) Machine Description
Your report should contain a reasonably detailed description of thetest machine(s). The relevant information should be available eitherfrom the system (e.g.,- Installation using the self-extracting archive (osx_x64_64_sfx.exe)
To install GAMS, please follow the steps below as closely as possible. We advise you to read this entire document before beginning the installation procedure. Furthermore, we recommend to use the PKG installer for Mac OS X because it includes the GAMS Studio and it integrates GAMS into Mac OS X, e.g. it is possible to open the GAMS Studio via the Launchpad.
Two installation procedures are available for GAMS on Mac OS X:
- Obtain the GAMS PKG file, which is available from http://www.gams.com/download.
- Double click the package and follow the instructions. By clicking on
Customise
in the tabInstallation Type
you can decide to add GAMS to the PATH as well as to reject the installation of GAMS Studio. Note that adding GAMS to the PATH is done by modifying your shell profile file (~/.zprofile
,~/.bash_profile
etc.). A backup of your old profile is saved (~/.zprofile.gamsbackup
,~/.bash_profile.gamsbackup
etc.). - In order to test the GAMS installation with
GAMS Studio
open theLaunchpad
and click theGAMS Studio 34
icon to open the application. Alternatively, go to Applications and open theGAMS Studio 34
application. Install your license via the corresponding GAMS Studio dialog. The license file is nowadays sent via email, with instructions. You can also request a demo license from http://www.gams.com/download.
Optionally, you can create the license file 'gamslice.txt' in a directory that GAMS searches to find a license. GAMS searches a couple of system wide and user specific standard locations for a license file.
- Open the
Model Library Explorer
and open theTRNSPORT
model (sequence number 001). Run the model and check the contents of the process log, which should be similar to the Terminal output listed in the next bullet point. In order to test the GAMS installation without using
GAMS Studio
open a Terminal window. Execute the following commands to see if everything works as expected:The output should be similar to this:
Showdown - Gam 120 Final Project Mac Os Catalina
To uninstall a GAMS installation that was installed using the PKG installer, run the following command from the terminal: sudo bash /Library/Frameworks/GAMS.framework/Versions/34/Resources/uninstall.sh
. Additionally, you can remove GAMS from the PATH in your shell profile file (~/.zprofile
, ~/.bash_profile
) if GAMS was added to the PATH during installation.
- Obtain the GAMS distribution file, which is available from http://www.gams.com/download, in one large self-extracting zip archive with a
_sfx.exe
file extension, e.g.,osx_x64_64_sfx.exe
. Check that it has the execute permission set. If you are not sure how to do this, just type in the commandchmod 755 osx_x64_64_sfx.exe
.- Attention
- The common way to install GAMS on a Mac is the PKG installer. When one tries to run the sfx installer (e.g. for unattended installation) under macOS 10.15 (Catalina) or newer, the installer and several related files will be tagged with the
com.apple.quarantine
flag. There are different solutions to this problem:- The flag can be removed by the following command:
- Instead of downloading the sfx installer through the browser, use a command line tool such as curl (note that by downloading the software, you agree to the License Agreement). The download link may need to be adjusted, depending on the distribution that should be downloaded.
- Choose a location where you want to create the GAMS system directory (the GAMS system directory is the directory where the GAMS system files should reside). At this location the GAMS installer will create a subdirectory with a name that indicates the distribution of GAMS you are installing. For example, if you are installing the 24.3 distribution in
/Applications/GAMS
, the installer will create the GAMS system directory/Applications/GAMS/gams24.3_osx_x64_64_sfx
. If the directory where you want to install GAMS is not below your home directory, you may need to have root privileges on the machine. - Create the directory that should contain the GAMS system directory, for instance
/Applications/GAMS
. Change to this directory (cd /Applications/GAMS
). Make surepwd
returns the name of this directory correctly. - Run the distribution file, either from its current location or after transfering it to the directory that should contain the GAMS system directory. By executing the distribution file, the GAMS distribution should be extracted. For example, if you downloaded the distribution file into your home directory, you might execute the following commands:
Create the license file
gamslice.txt
in a directory GAMS searches to find a license. The license file is nowadays sent via email, with instructions. You can also request a demo license from http://www.gams.com/download.- Attention
- Do not store the
gamslice.txt
in the GAMS system directory. This invalidates the code signature and cause Gatekeeper to reject the bundle!
GAMS searches a couple of system wide and user specific locations for a license file. For Mac OS X these locations include
/Library/Application Support/GAMS
and/Users/username/Library/Application Support/GAMS
. The locations can vary due to different system configuration. One can get an ordered list of data directories GAMS searches forgamslice.txt
by running the program./gamsinst -listdirs
from the GAMS system directory. Even though this list might contain locations in the system directory, e.g./Applications/GAMS31.1
we strongly discourage to placegamslice.txt
here.Change to the GAMS system directory and run the program
./gamsinst
. It will prompt you for default solvers to be used for each class of models. If possible, choose solvers you have licensed since unlicensed solvers will only run in demonstration mode. These solver defaults can be changed or overridden by:a. rerunning
./gamsinst
and resetting the default valuesb. setting a command line default, e.g.,
gams trnsport lp=soplex
c. an option statement in the GAMS model, e.g:
option lp=soplex;
- Add the GAMS system directory to your path (see below).
- To test the installation, log in as a normal user and run a few models from your home directory, but not the GAMS system directory:
- If you move the GAMS system to another directory, remember to rerun
./gamsinst
. It is also good practice to rerun./gamsinst
when you change your license file if this has changed the set of licensed solvers.
Access to GAMS
To run GAMS you must be able to execute the GAMS programs located in the GAMS system directory. There are several ways to do this. Remember that the GAMS system directory in the examples below may not correspond to the directory where you have installed your GAMS system.
- If you are using the C shell (
csh
) and its variants you can modify your.cshrc
file by adding the second of the two lines given below: - Those of you using the Bourne (
sh
) or Korn (ksh
) shells and their variants can modify their.profile
file by adding the second of the three lines below: If the.profile
file does not exist yet, it needs to be created. You should log out and log in again after you have made any changes to your path. - You may prefer to use an alias for the names of the programs instead of modifying the path as described above. C shell users can use the following commands on the command line or in their
.cshrc
file: The correct Bourne or Korn shell syntax (either command line or.profile
) is: Again, you should log out and log in in order to put the alias settings in.cshrc
or.profile
into effect. - Casual users can always type the absolute path names of the GAMS programs, e.g.:
Example
The following shows the log of a session, where a user downloads a GAMS 24.3.1 system and installs it under Applications/GAMS/gams24.3_osx_x64_64_sfx
. It is assumed that a GAMS license file has been stored as /Users/doe/gamslice.txt
.
Showdown - Gam 120 Final Project Mac Os Download
Winter 2020
Deadlines
Draft of Intro, Machine Description, and CPU Operations: | Tuesday, February 4 at 8am (start of class) |
Draft of Memory Operations: | |
Final report with all measurements plus code: | Thursday, March 12 at 8am (start of class) |
Overview
In building an operating system, it is important to be able todetermine the performance characteristics of underlying hardwarecomponents (CPU, RAM, disk, network, etc.), and to understand howtheir performance influences or constrains operating system services.Likewise, in building an application, one should understand theperformance of the underlying hardware and operating system, and howthey relate to the user's subjective sense of that application's'responsiveness'. While some of the relevant quantities can be foundin specs and documentation, many must be determined experimentally.While some values may be used to predict others, the relations betweenlower-level and higher-level performance are often subtle andnon-obvious.
In this project, you will create, justify, and apply a set ofexperiments to a system to characterize and understand itsperformance. In addition, you may explore the relations between someof these quantities. In doing so, you will study how to usebenchmarks to usefully characterize a complex system. You should alsogain an intuitive feel for the relative speeds of different basicoperations, which is invaluable in identifying performance bottlenecks.
You have complete choice over the operation system and hardwareplatform for your measurements. You can use your laptop that you arecomfortable with, an operating system running in a virtual machinemonitor, a smartphone, a game system, or even a supercomputer.
You may work either alone or in 2–3 person groups. Groupsdo the same project as individuals. All members receive the samegrade. Note that working in groups may or may not make the projecteasier, depending on how the group interactions work out. Ifcollaboration issues arise, contact your instructor as soon aspossible: flexibility in dealing with such issues decreases as thedeadline approaches.
This project has two parts. First, you will implement and performa series of experiments. Second, you will write a report documentingthe methodology and results of your experiments. When you finish, youwill submit your report as well as the code used to perform yourexperiments.
Report
Showdown - Gam 120 Final Project Mac Os X
Your report will have a number of sections including anintroduction, a machine description, and descriptions and discussionsof your experiments.
1) Introduction
Describe the goals of the project and, if you are in a group, whoperformed which experiments. State the language you used to implementyour measurements, and the compiler version and optimization settingsyou used to compile your code. If you are measuring in an unusualenvironment (e.g., virtual machine, Web browser, compute cloud, etc.),discuss the implications of the environment on the measurement task(e.g., additional variance that is difficult for you to control for).Estimate the amount of time you spent on this project.2) Machine Description
Your report should contain a reasonably detailed description of thetest machine(s). The relevant information should be available eitherfrom the system (e.g.,sysctl
on BSD, /proc
on Linux, System Profiler on Mac OS X, the cpuid
x86 instruction), or online. Gathering this informationshould not require much work, but in explaining and analyzing yourresults you will find these numbers useful. You should report atleast the following quantities:- Processor: model, cycle time, cache sizes (L1, L2, instruction, data, etc.)
- Memory bus
- I/O bus
- RAM size
- Disk: capacity, RPM, controller cache size
- Network card speed
- Operating system (including version/release)
3) Experiments
Perform your experiments by following these steps:- Estimate the base hardware performance of the operation and citethe source you used to determine this quantity (system info, aparticular document). For example, when measuring disk readperformance for a particular size, you can refer to the diskspecification (easily found online) to determine seek, rotation, andtransfer performance. Based on these values, you can estimate theaverage time to read a given amount of data from the disk assuming nosoftware overheads. For operations where the hardware performancedoes not apply or is difficult to measure (e.g., procedure call),state it as such.
- Make a guess as to how much overhead software will add to thebase hardware performance. For a disk read, this overhead willinclude the system call, arranging the read I/O operation, handlingthe completed read, and copying the data read into the user buffer.We will not grade you on your guess, this is for you to test yourintuition. (Obviously you can do this after performing the experimentto derive an accurate 'guess', but where is the fun in that?) For aprocedure call, this overhead will consist of the instructions used tomanage arguments and make the jump. Finally, if you are measuring asystem in an unusual environment (e.g., virtual machine, computecloud, Web browser, etc.), estimate the degree of variability anderror that might be introduced when performing your measurements.
- Combine the base hardware performance and your estimateof software overhead into an overall prediction of performance.
- Implement and perform the measurement. In all cases, you shouldrun your experiment multiple times, for long enough to obtainrepeatable measurements, and average the results. Also compute thestandard deviation across the measurements. Note that, when measuringan operation using many iterations (e.g., system call overhead),consider each run of iterations as a single trial and compute thestandard deviation across multiple trials (not each individualiteration).
- Use a low-overhead mechanism for reading timestamps. All modernprocessors have a cycle counter that applications can read using aspecial instruction(e.g., rdtsc).Searching for 'rdtsc' in Google, for instance, will provide you with aplethora of additional examples. Note, though, that in the modern ageof power-efficient multicore processors, you will need to takeadditional steps to reliably use the cycle counter to measure thepassage of time. You will want to disable dynamically adjusted CPUfrequency (the mechanism will depend on your platform) so that thefrequency at which the processor computes is determinstic and does notvary. Use 'nice' to boost your process priority. Restrictyour measurement programs to using a single core.
- Clearly explain the methodology of your experiment.
- Present your results:
- For measurements of single quantities (e.g., system calloverhead), use a table to summarize your results. In the tablereport the base hardware performance, your estimate of softwareoverhead, your prediction of operation time, and your measuredoperation time.
- For measurements of operations as a function of some otherquantity, report your results as a graph with operation time on they-axis and the varied quantity on the x-axis. Include your estimatesof base hardware performance and overall prediction of operation timeas curves on the graph as well.
- Discuss your results:
- Cite the source for the base hardware performance.
- Compare the measured performance with the predicted performance.If they are wildly different, speculate on reasons why. Whatmay be contributing to the overhead?
- Evaluate the success of your methodology. How accuratedo you think your results are?
- For graphs, explain any interesting features of the curves.
- Answer any questions specifically mentioned with the operation.
- At the end of your report, summarize your results in a table fora complete overview. The columns in your table should include'Operation', 'Base Hardware Performance', 'Estimated SoftwareOverhead', 'Predicted Time', and 'Measured Time'. (Not required forthe draft.)
- State the units of all reported values.
Do not underestimate the time it takes to describe your methodologyand results.
4) Operations
- CPU, Scheduling, and OS Services
- Measurement overhead: Report the overhead of reading time, and report the overhead of using a loop to measure many iterations of an operation.
- Procedure call overhead: Report as a function of number of integer arguments from 0-7. What is the increment overhead of an argument?
- System call overhead: Report the cost of a minimal system call. How does it compare to the cost of a procedure call? Note that some operating systems will cache the results of some system calls (e.g., idempotent system calls like getpid), so only the first call by a process will actually trap into the OS.
- Task creation time: Report the time to create and run both a process and a kernel thread (kernel threads run at user-level, but they are created and managed by the OS; e.g., pthread_create on modern Linux will create a kernel-managed thread). How do they compare?
- Context switch time: Report the time to context switch from one process to another, and from one kernel thread to another. How do they compare? In the past students have found using blocking pipes to be useful for forcing context switches. (For insight into why a context switch can be much more expensive than a procedure call, consider the evolution of the Linux kernel trap on x86.)
- Memory
- RAM access time: Report latency for individual integer accesses to main memory and the L1 and L2 caches. Present results as a graph with the x-axis as the log of the size of the memory region accessed, and the y-axis as the average latency. Note that the lmbench paper is a good reference for this experiment. In terms of the lmbench paper, measure the 'back-to-back-load' latency and report your results in a graph similar to Fig. 1 in the paper. You should not need to use information about the machine or the size of the L1, L2, etc., caches when implementing the experiment; the experiment will reveal these sizes. In your graph, label the places that indicate the different hardware regimes (L1 to L2 transition, etc.).
- RAM bandwidth: Report bandwidth for both reading and writing. Use loop unrolling to get more accurate results, and keep in mind the effects of cache line prefetching (e.g., see the lmbench paper).
- Page fault service time: Report the time for faulting an entire page from disk (mmap is one useful mechanism). Dividing by the size of a page, how does it compare to the latency of accessing a byte from main memory?
- Network
- Round trip time. Compare with the time to perform a ping (ICMP requests are handled at kernel level).
- Peak bandwidth.
- Connection overhead: Report setup and tear-down.
Evaluate for the TCP protocol. For each quantity, compare both remote and loopback interfaces. Comparing the remote and loopback results, what can you deduce about baseline network performance and the overhead of OS software? For both round trip time and bandwidth, how close to ideal hardware performance do you achieve? What are reasons why the TCP performance does not match ideal hardware performance (e.g., what are the pertinent overheads)? In describing your methodology for the remote case, either provide a machine description for the second machine (as above), or use two identical machines.
- File System
- Size of file cache: Note that the file cache size is determined by the OS and will be sensitive to other load on the machine; for an application accessing lots of file system data, an OS will use a notable fraction of main memory (GBs) for the file system cache. Report results as a graph whose x-axis is the size of the file being accessed and the y-axis is the average read I/O time. Do not use a system call or utility program to determine this metric except to sanity check.
- File read time: Report for both sequential and random access as a function of file size. Discuss the sense in which your 'sequential' access might not be sequential. Ensure that you are not measuring cached data (e.g., use the raw device interface). Report as a graph with a log/log plot with the x-axis the size of the file and y-axis the average per-block time.
- Remote file read time: Repeat the previous experiment for a remote file system. What is the 'network penalty' of accessing files over the network? You can either configure your second machine to provide remote file access, or you can perform the experiment on a department machine (e.g., APE lab). On these machines your home directory is mounted over NFS, so accessing a file under your home directory will be a remote file access (although, again, keep in mind file caching effects).
- Contention: Report the average time to read one file system block of data as a function of the number of processes simultaneously performing the same operation on different files on the same disk (and not in the file buffer cache).
References
During the quarter you will have read a number of papers describing various system measurements, particularly in the second half of the quarter. You may find those papers on the reading list useful as references.
In addition, other papers you may find useful for help with systemmeasurement are:
- John K. Ousterhout, WhyAren't Operating Systems Getting Faster as Fast as Hardware?,Proc. of USENIX Summer Conference, pp. 247-256, June 1990.
- J. Bradley Chen, Yasuhiro Endo, Kee Chan, David Mazières,Antonio Dias, Margo Seltzer, and Michael D. Smith, TheMeasured Performance of Personal Computer Operating Systems,Proc. of ACM SOSP, pp. 299-313, December 1995.
- Larry McVoy and Carl Staelin, lmbench:Portable Tools for Performance Analysis, Proc. of USENIX AnnualTechnical Conference, January 1996.
- Aaron B. Brown and Margo I. Seltzer, Operatingsystem benchmarking in the wake of lmbench: a case study of theperformance of NetBSD on the Intel x86 architecture, Proc. of ACM SIGMETRICS, pp. 214-224, June 1997.
- John Ousterhout, Always Measure One Level Deeper, Communications of the ACM, Vol. 61, No. 7, July 2018, pp. 74–83.
- Xiang (Jenny) Ren, Kirk Rodrigues, Luyuan Chen, Camilo Vega, Michael Stumm, and Ding Yuan, An Analysis of Performance Evolution of Linux's Core Operations, Proc. of the 27th ACM Symposium on Operating Systems Principles (SOSP 2019), pp. 554–569, October 2019.
- Gernot Heiser, Systems Benchmarking Crimes.
You may read these papers, or other references, for strategies onperforming measurements, but you may not examine code to copy orreplicate the implementation of a measurement. For example, readingthe lmbench paper is fine, but downloading and looking at the lmbenchcode violates the intent of the project.
Finally, it goes almost without saying that you must implement allof your measurements. You may not download a tool to perform themeasurements for you.
Grading
We will grade your project on the relative accuracy of yourmeasurement results (disk reads performing faster than the buffercache are a bad sign) as well as the quality of your report in termsof methodology description (can we understand what you did and why?),discussion of results (answering specific questions, discussingunexpected behavior), and the writing (lazy writing will hurt your grade).
In the past, a frequent issue we see with project reports is thatthey do not clearly explain the reasoning behind the estimates,methodology, results, etc. As a result, we do not fully understandwhat you did and why you did it that way. Be sure to explain yourreasoning as well.
As a first stage of the project, we would like you to submit anearly draft of the first part of the project. What should you coverin the draft? The first two parts of the report (Introduction and Machine Description), and the first set ofoperations (CPU, Scheduling, andOS Services). For this step only submit a draft of the report,not your code.
What percentage of the project grade does it form? It will onlybe worth 5% of your grade. Why so little? The idea with the initialdraft is that it is primarily for your own benefit: it will get youstarted on the project early, and it will give you a sense for howlong it will take you to complete the project by the end of thequarter (in the past, students have reported that it has taken them40-120 hours on the project). As a result, you should be able tobetter budget your time as the end of the quarter arrives. How roughcan the draft be? Your call — again, this is primarily for yourbenefit.
In the second stage of the project, extend your report draft withresults for the second set of operations (Memory). Please also hand in your gradedreport from the first stage for reference.
For the drafts, bring one hardcopy per group with you to class onthe deadline.
For the final project reports, submit them in pdf to me and the TA via email. Also submit your code to us via email as well, packaged either as a tar.gz or a zip file.