Hello,


Yet more precision about my inventions that are my SemaMonitor and
SemaCondvar and my Monitor..

My inventions that are my SemaMonitor and SemaCondvar are fast pathed
when the count of my SemaMonitor or my SemaCondvar is greater than 0, so
in this case the wait() method stays on the user mode and it doesn't
switch from user mode to kernel mode that costs around 1500 CPU cycles
and that is expensive, the signal() method is also fast pathed when
there is no item in the queue and count is less than MaximumCount, read
here about what is the cost (in CPU cycles) to switch between windows
user mode and kernel mode:

https://stackoverflow.com/questions/1368061/whats-the-cost-in-cycles-to-switch-between-windows-kernel-and-user-mode#:~:text=1%20Answer&text=Switching%20from%20%E2%80%9Cuser%20mode%E2%80%9D%20to,rest%20is%20%22kernel%20overhead%22.

You can read about and download my inventions of SemaMonitor and
SemaCondvar from here:

https://sites.google.com/site/scalable68/semacondvar-semamonitor

And the light weight version is here:

https://sites.google.com/site/scalable68/light-weight-semacondvar-semamonitor

And i have implemented an efficient Monitor over my SemaCondvar.

Here is the description of my efficient Monitor inside the Monitor.pas
file that you will find inside the zip file:

Description:

This is my implementation of a Monitor over my SemaCondvar.

You will find the Monitor class inside the Monitor.pas file inside the
zip file.

When you set the first parameter of the constructor to true, the signal
will not be lost if the threads are not waiting with wait() method, but
when you set the first parameter of the construtor to false, if the
threads are not waiting with the wait() method, the signal will be lost..

Second parameter of the constructor is the kind of Lock, you can set it
to ctMLock to use my scalable node based lock called MLock, or you can
set it to ctMutex to use a Mutex or you can set it to ctCriticalSection
to use the TCriticalSection.

Here is the methods of my efficient Monitor that i have implemented:

TMonitor = class
private
cache0:typecache0;
lock1:TSyncLock;
obj:TSemaCondvar;
cache1:typecache0;

public

constructor Create(bool:boolean=true;lock:TMyLocks=ctMLock);
destructor Destroy; override;
procedure Enter();
procedure Leave();
function Signal():boolean;overload;
function Signal(nbr:long;var remains:long):boolean;overload;
procedure Signal_All();
function Wait(const AMilliseconds:longword=INFINITE): boolean;
function WaitersBlocked():long;

end;


The wait() method is for the threads to wait on the Monitor object for
the signal to be signaled. If wait() fails, that can be that the number
of waiters is greater than high(longword).

And the signal() method will signal one time a waiting thread on the
Monitor object, but if signal() fails , the returned value is false.

the signal_all() method will signal all the waiting threads on
the Monitor object.

The signal(nbr:long;var remains:long) method will signal nbr of
waiting threads, but if signal() fails, the remaining number of signals
that were not signaled will be returned in the remains variable.

and WaitersBlocked() will return the number of waiting threads on
the Monitor object.

and Enter() and Leave() methods to enter and leave the monitor's Lock.


You can download the zip files from:

https://sites.google.com/site/scalable68/semacondvar-semamonitor

and the lightweight version is here:

https://sites.google.com/site/scalable68/light-weight-semacondvar-semamonitor


Thank you,
Amine Moulay Ramdane.

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