#include <a_samp>

public OnFilterScriptInit()
{
    SetTimer( "OneSecTimer", 1, true );

    return 1;
}

forward OneSecTimer( );
public  OneSecTimer( )
{
    static
        s_NextSecond = 0,
        s_PreviousTick = 0,
        s_Seconds = 0
    ;

    if ( s_NextSecond == 0 )
    {
        s_NextSecond = GetTickCount( ) + 1000;
        s_PreviousTick = GetTickCount( );
    }

    if ( GetTickCount( ) >= s_NextSecond )
    {
        s_Seconds++;

        printf( "%d - Ticks: %d", s_Seconds, GetTickCount( ) - s_PreviousTick );

        s_PreviousTick = GetTickCount( );

        s_NextSecond = GetTickCount( ) + 1000; // This is better than adding 999 to it each function call.
    }
}