Apache is a large-scale industrial multi-process and multi-threaded application, which uses lock-based synchronization. We have experimented with modifying Apache to employ transactional memory instead of locks, a process we refer to as transactification; we are not aware of any previous efforts to transactify legacy software of such a large scale. We have transactified apache's memory cache module mod_mem_cache using Intel's experimental STM C/C++ compiler.
stm_project.tar.bz2 tarball, or alternatively, you can aquire the latest version from the repository at github.
- Transactifying Apache paper submitted to SYSTOR'09
After downloading the project's tarball, the project main directory contains the following subdirectories:
- httpd-2.2.x The modified version of Apache, configured to use transactional memory
- httpd-2.2.x.no-transactions Another copy of the modified version of Apache, configured not to use transactional memory. cache-conf An Apache configuration folder configured to use the man2html workload, with mod_mem_cache enabled.
no-cache-conf An Apache configuration folder configured to use the man2html workload, with mod_mem_cache disabled.
- doc The documentation of the project, including this document, and the project’s presentation.
man The man program distribution, including the man2html cgi script.
man2html symbolic link into man/man2html/scripts, reffered to by Apache’s configuration folders cache-conf and no-cache-conf.
test Scripts needed for running the benchmarks.
runall_siege.py A script that runs all the needed experiments one by one.
- zipf_distrib.py A utility script that takes a list of URLs as an input, and outputs a list where every url appears a number of times according to Zipf distribution.
parse_results.py A script to convert the output of siege into a clean CSV file.
- url-lists A subdirectory with already generated URL lists.
- runall_siege.py A script that runs all the needed experiments one by one.
Server Side Installation
The following applies to both versions of apache.
- Install Intel STM C++ Compiler
- Install the schedtool utility for limiting the number of processors Apache will use.
- Unpack apr and apr-util packages into <httpd>srclib/apr and <httpd>/srclib/apr-util respectively. (Where <httpd> is the path of the version you are compiling).
- Configure apache using the parameters given in the configure-cmd file.
- Build using the make command.
- Configure and install the man2html program as described in man/INSTALL.
Client Side Installation
- Unpack, configure and install siege, from the siege-2.67.tar.gz file. Further information is in the package in the INSTALL and README files.
- Copy the URL lists from test/url-lists to the client machine.
This section elaborates the generation of URL lists for the client machines.
- The starting point for the process is a file containing a list of unique URLs, each in its own line.
Using the test/zipf_distrib.py program, a new list is created that is randomly distributed according to the Zipf distribution. The command line for doing that should be:
zipf_distrib.py s length < input-file > output-file
Where s is the s parameter of the Zipf distribution length is the number of URLs in the output. input-file is the input list of URLs. output-file is the output result.
The test/runall_siege.py script is intended to run from the server machine, and connect to the client by ssh. To avoid typing the password for every connection it is recommended to set up a public-key login to the client machine.
Before running, the following fields must be set in the script:
CLIENT_HOST Client host name.
- MAIN_DIR Directory where the project is placed.
SCHED_TOOL Path of the schedtool binary. (Can be just schedtool in case its on the system PATH).
URL_LISTS A list of filenames on the client host of the URL list files (Usually there is one for every s value needed in the experiment).
- MIN_CORES,MAX_CORES The minimum and maximum number of cores to test.
Set the siege output file in ~/.siegerc on the client machine, by editing the logfile entry.
Run the test/runall_siege.py script, the results will be saved on the client machine in the chosen output file.