delphi TParallel.For 老外得示例代码

program SystemThreadingTest;

{$APPTYPE CONSOLE}

uses

System.Diagnostics,

System.Threading;

const

maxItems = 5000;

DataSize = 100000;

procedure DoTest;

var

matches: integer;

i, j: integer;

sw: TStopWatch;

referenceStr: string;

begin

Randomize;

SetLength(referenceStr, DataSize);

for i := low(referenceStr) to high(referenceStr) do

referenceStr[i] := Chr(Ord('a') + Random(26));

// parallel

matches := 0;

sw := TStopWatch.StartNew;

TParallel.For(1, maxItems,

procedure(Value: integer)

var

index: integer;

found: integer;

begin

found := 0;

for index := low(referenceStr) to high(referenceStr) do

if (((Value mod 26) + Ord('a')) = Ord(referenceStr[index])) then

inc(found);

AtomicIncrement(matches, found);

end);

Writeln('Parallel matches: ', matches, ' in ', sw.ElapsedMilliseconds, 'ms');

// serial

matches := 0;

sw := TStopWatch.StartNew;

for i := 1 to maxItems do

for j := low(referenceStr) to high(referenceStr) do

if (((i mod 26) + Ord('a')) = Ord(referenceStr[j])) then

inc(matches);

Writeln('Serial matches: ', matches, ' in ', sw.ElapsedMilliseconds, 'ms');

end;

begin

while True do

DoTest;

end.

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