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-- Copyright (C) 1996 Morgan Kaufmann Publishers, Inc
-- This file is part of VESTs (Vhdl tESTs).
-- VESTs is free software; you can redistribute it and/or modify it
-- under the terms of the GNU General Public License as published by the
-- Free Software Foundation; either version 2 of the License, or (at
-- your option) any later version.
-- VESTs is distributed in the hope that it will be useful, but WITHOUT
-- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-- FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
-- for more details.
-- You should have received a copy of the GNU General Public License
-- along with VESTs; if not, write to the Free Software Foundation,
-- Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-- ---------------------------------------------------------------------
--
-- $Id: ch_19_srvr-b.vhd,v 1.2 2001-10-26 16:29:36 paw Exp $
-- $Revision: 1.2 $
--
-- ---------------------------------------------------------------------
library math;
architecture behavior of server is
begin
service : process is
variable served_token : token_type;
variable release_time : time;
variable number_of_tokens_served : natural := 0;
variable service_time : natural; -- in time_unit
variable sum_of_service_times : real := 0.0; -- in time_unit
variable sum_of_squares_of_service_times : real := 0.0; --in time_unit**2
variable random_info : random_info_record;
variable random_number : real;
use std.textio.all;
file info_file : text;
variable L : line;
use math.math_real.sqrt;
procedure write_summary is
variable measured_mean_service_time : real
:= sum_of_service_times / real(number_of_tokens_served);
variable measured_std_dev_of_service_times : real
:= sqrt ( ( sum_of_squares_of_service_times
- sum_of_service_times**2 / real(number_of_tokens_served) )
/ real( number_of_tokens_served - 1 ) );
begin
write(L, string'("Summary information for server "));
write(L, name);
write(L, string'(" up to time "));
write(L, now, unit => time_unit);
writeline(info_file, L);
write(L, string'(" Service distribution: "));
write(L, distribution_type'image(distribution));
write(L, string'(" with mean service time of "));
write(L, mean_service_time, unit => time_unit);
writeline(info_file, L);
write(L, string'(" Number of tokens served = "));
write(L, natural(number_of_tokens_served));
writeline(info_file, L);
write(L, string'(" Mean service time = "));
write(L, measured_mean_service_time * time_unit, unit => time_unit);
writeline(info_file, L);
write(L, string'(" Standard deviation of service times = "));
write(L, measured_std_dev_of_service_times * time_unit, unit => time_unit);
writeline(info_file, L);
write(L, string'(" Utilization = "));
write(L, sum_of_service_times / real(now / time_unit), digits => 4);
writeline(info_file, L);
writeline(info_file, L);
end procedure write_summary;
procedure write_trace_service is
begin
write(L, string'("Server "));
write(L, name);
write(L, string'(": at "));
write(L, now, unit => time_unit);
write(L, string'(" served "));
write(L, in_arc.token, time_unit);
writeline(info_file, L);
end procedure write_trace_service;
procedure write_trace_release is
begin
write(L, string'("Server "));
write(L, name);
write(L, string'(": at "));
write(L, now, unit => time_unit);
write(L, string'(" released "));
write(L, served_token, time_unit);
writeline(info_file, L);
end procedure write_trace_release;
begin
file_open(info_file, info_file_name, write_mode);
case distribution is
when fixed =>
init_fixed(random_info, real(mean_service_time / time_unit));
when uniform =>
init_uniform( random_info,
lower_bound => 0.0,
upper_bound => 2.0 * real(mean_service_time / time_unit),
seed => seed );
when exponential =>
init_exponential( random_info,
mean => real(mean_service_time / time_unit),
seed => seed );
end case;
in_ready <= true;
loop
wait on info_detail'transaction, in_arc;
if info_detail'active and info_detail = summary then
write_summary;
end if;
if in_arc'event then
in_ready <= false;
if info_detail = trace then
write_trace_service;
end if;
served_token := in_arc.token;
generate_random(random_info, random_number);
service_time := natural(random_number);
release_time := service_time * time_unit + now;
loop
wait on info_detail'transaction for release_time - now;
if info_detail'active and info_detail = summary then
write_summary;
end if;
exit when release_time = now;
end loop;
in_ready <= true;
out_arc <= arc_type'( transaction => not out_arc.transaction'driving_value,
token => served_token );
number_of_tokens_served := number_of_tokens_served + 1;
sum_of_service_times := sum_of_service_times + real(service_time);
sum_of_squares_of_service_times := sum_of_squares_of_service_times
+ real(service_time) ** 2;
if info_detail = trace then
write_trace_release;
end if;
end if;
end loop;
end process service;
end architecture behavior;
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