XREPL is a CPU hog

[racket-bug-submit]

Originally submitted by Stephen Austin on: Sun Mar 11 20:28:01 -0400 2012

In a racket REPL, (require xrepl) drives CPU use to ~94%.

Oddly, this does not occur if racket is started with "racket -il xrepl".

Steps to Reproduce:

Start racket in a terminal.
(require xrepl)

Release:

5.2.1

Environment:

macosx "Darwin sja-mbp.local 11.3.0 Darwin Kernel Version 11.3.0: Thu Jan 12 18:47:41 PST
 2012; root:xnu-1699.24.23~1/RELEASE_X86_64 x86_64" (x86_64-macosx/3m) (get-display-depth)
 = 32
Human Language: english
(current-memory-use) 389463672
Links: (links) = (); (links #:user? #f) = (); (links #:root? #t) = (); (links #:user? #f
 #:root? #t) = ()

Collections:
("/Users/antirealist/Library/Racket/5.2.1/collects"
 (non-existent-path))
("/Applications/Racket v5.2.1/collects"
 ("2htdp" "algol60" "at-exp" "browser" "combinator-parser" "compiler" "config" "data"
 "datalog" "db" "defaults" "deinprogramm" "drracket" "drscheme" "dynext" "embedded-gui"
 "eopl" "errortrace" "ffi" "file" "framework" "frtime" "games" "graphics" "gui-debugger"
 "help" "hierlist" "htdp" "html" "icons" "images" "info-domain" "lang" "launcher" "lazy"
 "macro-debugger" "make" "mred" "mrlib" "mysterx" "mzcom" "mzlib" "mzscheme" "net"
 "openssl" "parser-tools" "picturing-programs" "plai" "planet" "plot" "preprocessor"
 "profile" "r5rs" "r6rs" "racket" "racklog" "rackunit" "raco" "reader" "readline" "redex"
 "rnrs" "s-exp" "scheme" "schemeunit" "scribble" "scribblings" "scriblib" "setup" "sgl"
 "slatex" "slideshow" "srfi" "stepper" "string-constants" "swindle" "syntax"
 "syntax-color" "teachpack" "test-box-recovery" "test-engine" "tex2page" "texpict" "trace"
 "typed" "typed-racket" "typed-scheme" "unstable" "version" "web-server" "wxme" "xml"
 "xrepl"))

Computer Language: (("Determine language from source") (#(#t print mixed-fraction-e #f #f
 debug) (default) #() "#lang racket\n" #t #t))

This bug was converted from Gnats bug 12626.

[anon-submit; antirealist at gmail dot com]

[racket-bug-submit]

On Sun, 11 Mar 2012 20:36:53 -0400, eli at barzilay dot org wrote:

A few minutes ago, antirealist@gmail.com wrote:

In a racket REPL, (require xrepl) drives CPU use to ~94%.

Oddly, this does not occur if racket is started with "racket -il xrepl".

I don't think that xrepl does anything that could lead to that by itself, but maybe the problem is with firing up the readline reader?

Some questions:

1. Do you actually get a working (x)repl after the require?
2. If not, then what backtrace do you see when you hit Ctrl+C?
3. What happens when you try (require readline/rep) in the repl?

4. Is it also similarly broken if you put the (require xrepl) line in your racketrc file?

   To see where the file is expected to be, evaluate this: (find-system-path 'init-file). (Note that the file should not have a `#lang' line!)

      ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                http://barzilay.org/                   Maze is Life!

[racket-bug-submit]

On Sun, 11 Mar 2012 19:45:24 -0500, robby at eecs dot northwestern dot edu wrote:

It happens on my macosx machine, so probably you can find yourself a machine at NEU to reproduce this problem. I guess that'll be faster than this conversation.

On Sun, Mar 11, 2012 at 7:36 PM, Eli Barzilay <eli@barzilay.org> wrote:
> A few minutes ago, antirealist@gmail.com wrote:
>> In a racket REPL, (require xrepl) drives CPU use to ~94%.
>>
>> Oddly, this does not occur if racket is started with "racket -il
>> xrepl".
>
> I don't think that xrepl does anything that could lead to that by
> itself, but maybe the problem is with firing up the readline reader?
>
> Some questions:
>
> 1. Do you actually get a working (x)repl after the require?
>
> 2. If not, then what backtrace do you see when you hit Ctrl+C?
>
> 3. What happens when you try (require readline/rep) in the repl?
>
> 4. Is it also similarly broken if you put the (require xrepl) line in
>   your racketrc file?
>
>   To see where the file is expected to be, evaluate this:
>   (find-system-path 'init-file).  (Note that the file should not have
>   a `#lang' line!)
>
> --
>          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
>                    http://barzilay.org/                   Maze is Life!

[racket-bug-submit]

On Mon, 12 Mar 2012 08:05:44 -0700, clements at brinckerhoff dot org wrote:

--Apple-Mail=_487F7D25-93BA-4F3D-82E2-2F60EB3DD54D Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii

On Mar 11, 2012, at 5:36 PM, Eli Barzilay wrote:

A few minutes ago, antirealist@gmail.com wrote:

In a racket REPL, (require xrepl) drives CPU use to ~94%.

Oddly, this does not occur if racket is started with "racket -il xrepl".

I don't think that xrepl does anything that could lead to that by itself, but maybe the problem is with firing up the readline reader?

What the heck, students taking exams, I can reproduce this as well:

Some questions:

1. Do you actually get a working (x)repl after the require?

Yes.

1. If not, then what backtrace do you see when you hit Ctrl+C?

N/A.

1. What happens when you try (require readline/rep) in the repl?

99% CPU, same as the above issue.

1. Is it also similarly broken if you put the (require xrepl) line in your racketrc file?

No, putting it in my .racketrc does not lead to increased CPU, I see the xrepl prompt and everything seems fine.

John

To see where the file is expected to be, evaluate this: (find-system-path 'init-file). (Note that the file should not have a `#lang' line!)

     ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
               http://barzilay.org/                   Maze is Life!

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[dyoo]

This should be closed now; got it fixed recently in f1e70516524b96c6746a4004393b57aa46b7eb84

[samth]

@dyoo, I don't think you meant to comment here.