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diff --git a/docs/tutorials/018/combine.shar b/docs/tutorials/018/combine.shar deleted file mode 100644 index a653d49c3ce..00000000000 --- a/docs/tutorials/018/combine.shar +++ /dev/null @@ -1,440 +0,0 @@ -#!/bin/sh -# This is a shell archive (produced by GNU sharutils 4.2). -# To extract the files from this archive, save it to some FILE, remove -# everything before the `!/bin/sh' line above, then type `sh FILE'. -# -# Made on 2000-03-19 15:00 EST by <jcej@chiroptera.tragus.org>. -# Source directory was `/home/jcej/projects/ACE_wrappers/docs/tutorials/018'. -# -# Existing files will *not* be overwritten unless `-c' is specified. -# -# This shar contains: -# length mode name -# ------ ---------- ------------------------------------------ -# 416 -rw-rw-r-- hdr -# 64 -rw-rw-r-- bodies -# 2586 -rw-rw-r-- page01.pre -# 430 -rw-rw-r-- page02.pre -# 1279 -rw-rw-r-- page03.pre -# 688 -rw-rw-r-- page04.pre -# 259 -rw-rw-r-- page05.pre -# 1519 -rw-rw-r-- page06.pre -# 476 -rw-rw-r-- page07.pre -# -save_IFS="${IFS}" -IFS="${IFS}:" -gettext_dir=FAILED -locale_dir=FAILED -first_param="$1" -for dir in $PATH -do - if test "$gettext_dir" = FAILED && test -f $dir/gettext \ - && ($dir/gettext --version >/dev/null 2>&1) - then - set `$dir/gettext --version 2>&1` - if test "$3" = GNU - then - gettext_dir=$dir - fi - fi - if test "$locale_dir" = FAILED && test -f $dir/shar \ - && ($dir/shar --print-text-domain-dir >/dev/null 2>&1) - then - locale_dir=`$dir/shar --print-text-domain-dir` - fi -done -IFS="$save_IFS" -if test "$locale_dir" = FAILED || test "$gettext_dir" = FAILED -then - echo=echo -else - TEXTDOMAINDIR=$locale_dir - export TEXTDOMAINDIR - TEXTDOMAIN=sharutils - export TEXTDOMAIN - echo="$gettext_dir/gettext -s" -fi -touch -am 1231235999 $$.touch >/dev/null 2>&1 -if test ! -f 1231235999 && test -f $$.touch; then - shar_touch=touch -else - shar_touch=: - echo - $echo 'WARNING: not restoring timestamps. Consider getting and' - $echo "installing GNU \`touch', distributed in GNU File Utilities..." - echo -fi -rm -f 1231235999 $$.touch -# -if mkdir _sh00359; then - $echo 'x -' 'creating lock directory' -else - $echo 'failed to create lock directory' - exit 1 -fi -# ============= hdr ============== -if test -f 'hdr' && test "$first_param" != -c; then - $echo 'x -' SKIPPING 'hdr' '(file already exists)' -else - $echo 'x -' extracting 'hdr' '(text)' - sed 's/^X//' << 'SHAR_EOF' > 'hdr' && -<HTML> -<HEAD> -X <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> -X <META NAME="Author" CONTENT="James CE Johnson"> -X <TITLE>ACE Tutorial 018</TITLE> -</HEAD> -<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F"> -X -<CENTER><B><FONT SIZE=+2>ACE Tutorial 018</FONT></B></CENTER> -X -<CENTER><B><FONT SIZE=+2>The FIFO Nature of ACE_Token</FONT></B></CENTER> -X -<P> -<HR WIDTH="100%"> -SHAR_EOF - $shar_touch -am 03191459100 'hdr' && - chmod 0664 'hdr' || - $echo 'restore of' 'hdr' 'failed' - if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ - && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then - md5sum -c << SHAR_EOF >/dev/null 2>&1 \ - || $echo 'hdr:' 'MD5 check failed' -66dbcd27e23cdcc9c230089e9c289bcb hdr -SHAR_EOF - else - shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'hdr'`" - test 416 -eq "$shar_count" || - $echo 'hdr:' 'original size' '416,' 'current size' "$shar_count!" - fi -fi -# ============= bodies ============== -if test -f 'bodies' && test "$first_param" != -c; then - $echo 'x -' SKIPPING 'bodies' '(file already exists)' -else - $echo 'x -' extracting 'bodies' '(text)' - sed 's/^X//' << 'SHAR_EOF' > 'bodies' && -PAGE=2 -token.cpp -Test_T.h -Test_T.cpp -Token_i.h Mutex_i.h -output -SHAR_EOF - $shar_touch -am 1114165298 'bodies' && - chmod 0664 'bodies' || - $echo 'restore of' 'bodies' 'failed' - if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ - && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then - md5sum -c << SHAR_EOF >/dev/null 2>&1 \ - || $echo 'bodies:' 'MD5 check failed' -22e70b25b6f23655b44d31fcf1a669f8 bodies -SHAR_EOF - else - shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'bodies'`" - test 64 -eq "$shar_count" || - $echo 'bodies:' 'original size' '64,' 'current size' "$shar_count!" - fi -fi -# ============= page01.pre ============== -if test -f 'page01.pre' && test "$first_param" != -c; then - $echo 'x -' SKIPPING 'page01.pre' '(file already exists)' -else - $echo 'x -' extracting 'page01.pre' '(text)' - sed 's/^X//' << 'SHAR_EOF' > 'page01.pre' && -X -Welcome to Tutorial 18! -<P> -We've seen various ACE methods for synchronization in this and other -tutorial sections. Something we haven't yet seen is the ACE_Token. -ACE_Token has a really cool thing: it behaves in a FIFO manner. -<P> -Why is that cool? -<P> -In the other tutorials, you may have found that one thread will end up -with all of the work. Even though other threads are available, the OS -scheduling and lock management just causes it to happen. With -ACE_Token, the threads are queued up on the token and served in a -traditional first-in-first-out manner. -<P> -Why is FIFO important? -<P> -Well, if your app is running in a bunch of threads and each is doing -the same thing on the local host then FIFO may not be important. -However, take the case where each thread is connected to a remote -system. Let's say you have a dozen threads in your app and each is -connected to a different remote system. Each of the threads will be -given a block of data which will be passed to the remote for some -intense calculation. If you use the FIFO then you'll spread the work -more-or-less evenly between the remote peers. If you use the -traditional mutex then one peer may get the lion's share of the work. -<P> -It gets down to a personal decision based on the application's needs. -Consider your application, examine its behavior & decide for yourself -if you want to spread the work evenly or if it's OK to let some -threads work harder than others. -<P> -Kirthika's abstract: -<UL> -A token is similar to a mutex-lock, with the difference being that -the token is given to the waiting threads in a FIFO order. In the case -of the mutex-lock, any thread (depending on the OS) could acquire -the lock when its released. It internally implements a recursive mutex, -i.e. the thread that owns the mutex can reqacquire it without deadlocking. -The token also has two FIFO lists for writers and readers with writer- -acquires having a higher priority than reader-acquires. -<P> -This tutorial throws light on the differences on having a shared resource governed by -a lock and a token, both derive from a Task which simply updates a counter with the -number-of-threads value. A barrier is used for ensuring that all threads get a equal -opportunity of grabbing the token. The message queue with the message containing the -thread count moves among the threads to be obtained and read. -<P> -On obtaining the results, we conclude that on using the Token, the job to be completed -can be distributed evenly among available threads. This cant be guaranteed -in case of simply using the lock for synchronisation. -</ul> -SHAR_EOF - $shar_touch -am 03191459100 'page01.pre' && - chmod 0664 'page01.pre' || - $echo 'restore of' 'page01.pre' 'failed' - if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ - && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then - md5sum -c << SHAR_EOF >/dev/null 2>&1 \ - || $echo 'page01.pre:' 'MD5 check failed' -c2c450403d3a23fb5c1d2f1dc23a1eb4 page01.pre -SHAR_EOF - else - shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page01.pre'`" - test 2586 -eq "$shar_count" || - $echo 'page01.pre:' 'original size' '2586,' 'current size' "$shar_count!" - fi -fi -# ============= page02.pre ============== -if test -f 'page02.pre' && test "$first_param" != -c; then - $echo 'x -' SKIPPING 'page02.pre' '(file already exists)' -else - $echo 'x -' extracting 'page02.pre' '(text)' - sed 's/^X//' << 'SHAR_EOF' > 'page02.pre' && -Our main() just keeps getting simpler! I guess that's a good thing. -<P> -What we've done is create two Task-derived objects that test different -locking mechanisms. The Token object uses ACE_Token and the Mutex -object uses ACE_Mutex. When you execute the application you should -see quite a difference in thread utilization. At the end of the -tutorial I've included a link to the output of a typical run of the -application. -<HR> -SHAR_EOF - $shar_touch -am 03191459100 'page02.pre' && - chmod 0664 'page02.pre' || - $echo 'restore of' 'page02.pre' 'failed' - if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ - && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then - md5sum -c << SHAR_EOF >/dev/null 2>&1 \ - || $echo 'page02.pre:' 'MD5 check failed' -a36353959f7874c8e31884d2acd7eb43 page02.pre -SHAR_EOF - else - shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page02.pre'`" - test 430 -eq "$shar_count" || - $echo 'page02.pre:' 'original size' '430,' 'current size' "$shar_count!" - fi -fi -# ============= page03.pre ============== -if test -f 'page03.pre' && test "$first_param" != -c; then - $echo 'x -' SKIPPING 'page03.pre' '(file already exists)' -else - $echo 'x -' extracting 'page03.pre' '(text)' - sed 's/^X//' << 'SHAR_EOF' > 'page03.pre' && -Our Test object is a simple derivative of ACE_Task. Although we've -certainly used templates in other tutorials, this is the first time -we've created one of our own. -<P> -In a lot of ways, you can think of templates as the sophisticated -cousin of the old C-style pre-processor macros. With templates, -however, you get better type-checking and much easier debugging. There -are certainly other benefits but these are my favorites. -<P> -Our template's MUTEX parameter is used to set the mutex type -<i>mutex_t</i>. That'll be used in svc() so that we can protect -shared resources needed during the processing of data received on our -message queue. -<P> -Note at the bottom how we have to include the <i>cpp</i> file -associated with us. Most compilers have to see the definition of -templated classes along with their declaration. You might be tempted, -therefore, to just put the definitions in the header file. Resist -that temptation because templates are one of the fastest growing areas -of compilers. Including the definition like we do here leads to long -compile times and overly-large binaries. With luck, the compilers -will get smarter in the future and we won't need definition -inclusion. If you've already got them broken out then you'll save -yourself a lot of time! -<HR> -SHAR_EOF - $shar_touch -am 03191459100 'page03.pre' && - chmod 0664 'page03.pre' || - $echo 'restore of' 'page03.pre' 'failed' - if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ - && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then - md5sum -c << SHAR_EOF >/dev/null 2>&1 \ - || $echo 'page03.pre:' 'MD5 check failed' -68432fc61bf23fe391f4ead60fe26b17 page03.pre -SHAR_EOF - else - shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page03.pre'`" - test 1279 -eq "$shar_count" || - $echo 'page03.pre:' 'original size' '1279,' 'current size' "$shar_count!" - fi -fi -# ============= page04.pre ============== -if test -f 'page04.pre' && test "$first_param" != -c; then - $echo 'x -' SKIPPING 'page04.pre' '(file already exists)' -else - $echo 'x -' extracting 'page04.pre' '(text)' - sed 's/^X//' << 'SHAR_EOF' > 'page04.pre' && -Our Test implementation looks much like the other ACE_Task derivatives -we've used in the past. The most obvious change is the addition of -the run() method. run() will activate the threads and put a few -messages into the queue. We could have done that in main() but it -just makes more sense here. -<P> -Notice how svc() grabs the guard after getting a message from the -queue. Since we constructed our Task baseclass with ACE_MT_SYNCH, we -know that the queue is already thread-safe. Our purpose in grabbing -the additional lock is to show how ACE_Token and ACE_Mutex behave -differently. In a real app, you'd be doing this to protect shared -resources that the threads might clobber. -<HR> -SHAR_EOF - $shar_touch -am 03191459100 'page04.pre' && - chmod 0664 'page04.pre' || - $echo 'restore of' 'page04.pre' 'failed' - if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ - && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then - md5sum -c << SHAR_EOF >/dev/null 2>&1 \ - || $echo 'page04.pre:' 'MD5 check failed' -51ea4870a85f49c113951fedd695e35f page04.pre -SHAR_EOF - else - shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page04.pre'`" - test 688 -eq "$shar_count" || - $echo 'page04.pre:' 'original size' '688,' 'current size' "$shar_count!" - fi -fi -# ============= page05.pre ============== -if test -f 'page05.pre' && test "$first_param" != -c; then - $echo 'x -' SKIPPING 'page05.pre' '(file already exists)' -else - $echo 'x -' extracting 'page05.pre' '(text)' - sed 's/^X//' << 'SHAR_EOF' > 'page05.pre' && -Here we create simple derivatives of our Test templated class. Each -is parameterized with our mutex of choice and "named". Using the Test -template we're able to reuse all of the code with practially no -retyping and certainly much less chance of error! -<HR> -SHAR_EOF - $shar_touch -am 03191459100 'page05.pre' && - chmod 0664 'page05.pre' || - $echo 'restore of' 'page05.pre' 'failed' - if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ - && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then - md5sum -c << SHAR_EOF >/dev/null 2>&1 \ - || $echo 'page05.pre:' 'MD5 check failed' -31b8531c267e036e6f463249cd04b53a page05.pre -SHAR_EOF - else - shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page05.pre'`" - test 259 -eq "$shar_count" || - $echo 'page05.pre:' 'original size' '259,' 'current size' "$shar_count!" - fi -fi -# ============= page06.pre ============== -if test -f 'page06.pre' && test "$first_param" != -c; then - $echo 'x -' SKIPPING 'page06.pre' '(file already exists)' -else - $echo 'x -' extracting 'page06.pre' '(text)' - sed 's/^X//' << 'SHAR_EOF' > 'page06.pre' && -That's it for the code, now let's take a quick look at some output. -The first set of output is from the Token test, the second is Mutex -test. Notice how the threads are evenly utilized in the Token test. -Each thread gets to see exactly two messages. There's also an -interesting side-effect that the messages are processed in order. (You -can't rely on that, it just happend in this particular run.) -<P> -With the Mutex test, however, we see that the first thread gets no -less than 1/2 of all messages. In fact, if we didn't have the -governor in svc() it might have gotten them all! -<P> -Why does this happen? -<P> -Primarily because of time slicing. Even though each thread takes time -to do work (1 second in our test), it can still own the timeslice when -it gets back to the mutex acquire. Since the other threads are still -switched out, the current thread regets the lock and continues. On -the other hand, the ACE_Token is very careful about the order in which -the acquisition is allowed and more evenly distributes the work. -<P> -Play around with the sleep() call in svc(). You'll find that as you -decrease it, there is more chance that even the Token test will do -most of its work in one thread. You're still at the mercy of the OS -time slicing. In reality, though, it will take a moment or two for -work to be done. The end goal isn't necessarily to distribute the -work evenly over all threads but, rather, to distribute it evenly -among <i>available</i> threads. The distinction is subtle but important. -<HR> -SHAR_EOF - $shar_touch -am 03191459100 'page06.pre' && - chmod 0664 'page06.pre' || - $echo 'restore of' 'page06.pre' 'failed' - if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ - && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then - md5sum -c << SHAR_EOF >/dev/null 2>&1 \ - || $echo 'page06.pre:' 'MD5 check failed' -ac415a062a971ba79a088d929dda5f36 page06.pre -SHAR_EOF - else - shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page06.pre'`" - test 1519 -eq "$shar_count" || - $echo 'page06.pre:' 'original size' '1519,' 'current size' "$shar_count!" - fi -fi -# ============= page07.pre ============== -if test -f 'page07.pre' && test "$first_param" != -c; then - $echo 'x -' SKIPPING 'page07.pre' '(file already exists)' -else - $echo 'x -' extracting 'page07.pre' '(text)' - sed 's/^X//' << 'SHAR_EOF' > 'page07.pre' && -And now we're at the end of another Tutorial. As always, feel free to -send in questions and comments. There are certainly more -implementation possibilites and I'll gladly integrate yours into these -Tutorials. -<P> -<UL> -<LI><A HREF="Makefile">Makefile</A> -<LI><A HREF="token.cpp">token.cpp</A> -<LI><A HREF="Test.h">Test.h</A> -<LI><A HREF="Test.cpp">Test.cpp</A> -<LI><A HREF="Token_i.h">Token_i.h</A> -<LI><A HREF="Mutex_i.h">Mutex_i.h</A> -<LI><A HREF="output">output</A> -</UL> -SHAR_EOF - $shar_touch -am 03191459100 'page07.pre' && - chmod 0664 'page07.pre' || - $echo 'restore of' 'page07.pre' 'failed' - if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ - && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then - md5sum -c << SHAR_EOF >/dev/null 2>&1 \ - || $echo 'page07.pre:' 'MD5 check failed' -b7e7273c9bbeec45bdf2df2e8af06323 page07.pre -SHAR_EOF - else - shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page07.pre'`" - test 476 -eq "$shar_count" || - $echo 'page07.pre:' 'original size' '476,' 'current size' "$shar_count!" - fi -fi -rm -fr _sh00359 -exit 0 |