[Tcl-bugs] [ tcl-Bugs-781585 ] Interpreter 10 time slower then 8.3.3

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Bugs item #781585, was opened at 2003-08-01 13:22
Message generated for change (Comment added) made by msofer
You can respond by visiting: 
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>Category: 46. Bytecode Compiler
Group: 8.4.4
Status: Open
Resolution: None
Priority: 5
Submitted By: Franco Violi (effevi)
Assigned to: Jeffrey Hobbs (hobbs)
Summary: Interpreter 10 time slower then 8.3.3

Initial Comment:
This small program show something wrong on 8.4.4 against 
8.3.3. Try as is on 8.4.4 and the do the same uncommenting 
the append statement. 
 
#!/usr/bin/tngsh 
set buffout [string repeat x 3000000] 
proc goappend {} { 
	global buffout 
	switch x { 
		x { 
			append buffout "1" 
		} 
	} 
# 
# uncomment this line to see the code much more slower !! 
# 
#	append buffout "x" 
# 
	return 1 
} 
 
for {set i 0} {$i < 3000} {incr i} { 
	goappend 
	puts "append $i" 
} 
 

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>Comment By: miguel sofer (msofer)
Date: 2003-08-01 23:30

Message:
Logged In: YES 
user_id=148712

Verified in 8.4.3 and 8.4.2 too. The following script
isolates a bit the probable causes:
  - [switch] is innocent; what seems to cause the problem is
that append is called "mixed" (once bytecompiled, once invoked)
   - it is not obvious that it is caused by the new variable
tclObjTypes (but they remain a prime suspect tomy eyes)
   - [global] is innocent, although it is important that
this a global variable. The behaviour is identical if we use
[global buffout] instead of the fully qualified name ::buffout

set buffout [string repeat x 300000] 
proc goappend {w} { 
    set append append
    if {$w == 0} {
	$append ::buffout "1"
	$append ::buffout "1" 
    } elseif {$w == 1} {
	$append ::buffout "1"
	append ::buffout "1"
    } else {
	append ::buffout "1"
	append ::buffout "1"
    }
} 
puts [info patch]
puts [time {goappend 0} 3000]
puts [time {goappend 1} 3000]
puts [time {goappend 2} 3000]

Output:

8.4.3
13 microseconds per iteration
2273 microseconds per iteration
11 microseconds per iteration

8.4.2
8 microseconds per iteration
2231 microseconds per iteration
7 microseconds per iteration

8.3.4
13 microseconds per iteration
13 microseconds per iteration
12 microseconds per iteration


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