A fast Transcript

Hi Eliot,

Just a question: Could you describe the situations when you need to have the Transcript editable?

I am not trying to provoke you,

but to understand use cases. While working on GT I found that it is often possible to support the same use cases with multiple UI solutions. And sometimes considering alternatives leads to interesting results.

Cheers,

Doru

On Sat, May 9, 2015 at 9:32 PM, Eliot Miranda <[hidden email]> wrote:

Hi Juan,

    I see that your new transcript is indeed much faster but is also not editable.  I wonder if it would be possible to have the best of both worlds and arrange that, when active, the transcript is editable.  For example, selecting the TranscriptWIndow could put it into a mode where the transcript's state was imported into a more conventional editable text morph, and then when the window was exited, reverted to the standard fast output mode.  As you can infer I like having an editable transcript.  I can do without it, because Squeak's slow transcript is indeed a PITA, but I'm not sure that speed need preclude editability.

On Sat, May 9, 2015 at 10:17 AM, J. Vuletich (mail lists) <[hidden email]> wrote:

Hi Folks,

(below)

Quoting Ben Coman <[hidden email]>:

On Sat, May 9, 2015 at 10:35 PM, Eliot Miranda <[hidden email]>
wrote:

On Sat, May 9, 2015 at 7:09 AM, Ben Coman <[hidden email]> wrote:

From my limited experience bug hunting, calling #changed: from a thread
other than the UI thread is a source of evil.  There are too many
assumptions throughout the system that the UI is single threaded.  Can
anyone advise me that is not a proper belief?

Then that implies that a Transcript implementation where #nextPut: direct
calls #changed:
is not appropriate for use with multi-threaded applications.  In Pharo,
#changed: is only called from #stepGlobal, which is called from
doOneCycle:.  (This came about as a last minute bug fix before Pharo 3
release and maybe could use some cleanup.

Separating the UI from Transcript into its own viewer might be a good
idea, but actually it would not solve Stef's case since his code would
still be running in the UI thread -- unless the viewer ran in another
thread, which would have its own complexities.

I think the point about efficiency is significant. The following
example...
     Time millisecondsToRun: [ 1000 timesRepeat:  [ Transcript show: 'x'
] ]
on Squeak 4.5 --> 12749ms
on Pharo 50029 --> 2ms

This better performance helped me a lot trying to understand the high
priority timerEventLoop being able to indiscriminately scatter Transcript
tracing through that code.  I believe its also probably beneficial for
working with externally triggered semaphores and timing sensitive race
conditions.

So we have two mutually exclusive cases:
* better interactivity, poorer system performance
* faster system performance, worse interactivity

Which of these is broken depends on your viewpoint.

Something that runs fast but is incorrect is still incorrect.  The fact
that the transcript doesn't output until a world step is possible is a
bug.  It forces programs that use the transcript to be rewritten in order
to see transcript output.

As a point of comparison for correctness, for the following...

    Transcript clear.
    [   $a asciiValue to: $z asciiValue do: [ :c |
  [ 1 to: 9 do: [ :i | Transcript show: c asCharacter printString , i
printString , ' ' ] ] forkAt: 40
].
    ] forkAt: 41

Squeak 4.5 gives...
$a1 $a2 $a3 $a4 $a5 $a6 $a7 $a8 $a9 $b1 $b2 $b3 $b4 $b5 $b5 $c1 $c2 $c3 $c4
$c5 $c6 $c7 $c8 $c9 $d1 $d2 $d3 $d4 $d5 $d6 $d7 $d8 $d9 $d9 $e2 $g2 $h2 $h2
$i2 $k2 $k2 $l2 $n2 $n2 $o2 $o2 $r2 $s2 $t2 $u2 $u2 $v2 $x2 $y2 $z2 $z2 $b7
$f3 $e3 $e3 $g3 $j3 $h3 $i3 $k3 $k3 $m3 $n3 $p3 $p3 $q3 $o3 $s3 $t3 $t3 $u3
$v3 $x3 $y3 $z3 $b8 $f4 $e4 $e4 $g4 $h4 $i4 $k4 $l4 $m4 $m4 $n4 $r4 $q4 $o4
$o4 $s4 $w4 $u4 $u4 $v4 $y4 $y4 $z4 $z4 $f5 $j5 $j5 $g5 $i5 $k5 $l5 $l5 $m5
$m5 $n5 $q5 $o5 $s5 $s5 $t5 $u5 $u5 $x5 $y5 $z5 $f6 $f6 $h6 $h6 $g6 $g6 $k6
$p6 $m6 $r6 $r6 $n6 $o6 $s6 $s6 $w6 $u6 $x6 $x6 $e7 $f7 $j7 $h7 $h7 $i7 $l7
$l7 $k7 $m7 $m7 $q7 $n7 $n7 $o7 $t7 $w7 $w7 $u7 $v7 $x7 $z7 $z7 $e8 $e8 $h8
$g8 $i8 $i8 $l8 $k8 $k8 $m8 $q8 $n8 $n8 $s8 $t8 $w8 $y8 $y8 $u8 $x8 $z8 $f9
$f9 $e9 $h9 $h9 $g9 $p9 $p9 $k9 $r9 $r9 $m9 $n9 $n9 $o9 $t9 $t9 $w9 $v9 $u9
$u9 $z9 $x9

Pharo 50041 gives...
$a1 $a2 $a3 $a4 $a5 $a6 $a7 $a8 $a9 $b1 $b2 $b3 $b4 $b5 $b6 $b7 $b8 $b9 $c1
$c2 $c3 $c4 $c5 $c6 $c7 $c8 $c9 $d1 $d2 $d3 $d4 $d5 $d6 $d7 $d8 $d9 $e1 $e2
$e3 $e4 $e5 $e6 $e7 $e8 $e9 $f1 $f2 $f3 $f4 $f5 $f6 $f7 $f8 $f9 $g1 $g2 $g3
$g4 $g5 $g6 $g7 $g8 $g9 $h1 $h2 $h3 $h4 $h5 $h6 $h7 $h8 $h9 $i1 $i2 $i3 $i4
$i5 $i6 $i7 $i8 $i9 $j1 $j2 $j3 $j4 $j5 $j6 $j7 $j8 $j9 $k1 $k2 $k3 $k4 $k5
$k6 $k7 $k8 $k9 $l1 $l2 $l3 $l4 $l5 $l6 $l7 $l8 $l9 $m1 $m2 $m3 $m4 $m5 $m6
$m7 $m8 $m9 $n1 $n2 $n3 $n4 $n5 $n6 $n7 $n8 $n9 $o1 $o2 $o3 $o4 $o5 $o6 $o7
$o8 $o9 $p1 $p2 $p3 $p4 $p5 $p6 $p7 $p8 $p9 $q1 $q2 $q3 $q4 $q5 $q6 $q7 $q8
$q9 $r1 $r2 $r3 $r4 $r5 $r6 $r7 $r8 $r9 $s1 $s2 $s3 $s4 $s5 $s6 $s7 $s8 $s9
$t1 $t2 $t3 $t4 $t5 $t6 $t7 $t8 $t9 $u1 $u2 $u3 $u4 $u5 $u6 $u7 $u8 $u9 $v1
$v2 $v3 $v4 $v5 $v6 $v7 $v8 $v9 $w1 $w2 $w3 $w4 $w5 $w6 $w7 $w8 $w9 $x1 $x2
$x3 $x4 $x5 $x6 $x7 $x8 $x9 $y1 $y2 $y3 $y4 $y5 $y6 $y7 $y8 $y9 $z1 $z2 $z3
$z4 $z5 $z6 $z7 $z8 $z9

(start your comparison at $b5)

So in one axis Pharo has improved Transcript, but we didn't notice the
significance of the use case we lost.

cheers -ben

Please take a good look at Cuis' Transcript and consider using it.

By default, the display is updated immediately, but without calling Morphic, it can even work with no UI framework at all. It does updates faster than Squeak or Visualworks:

        Time millisecondsToRun: [ 1000 timesRepeat:  [ Transcript show: 'x' ] ]. 763.

But if you want minimum overhead without immediate feedback:

        Time millisecondsToRun: [ Transcript showOnDisplay: false. 1000 timesRepeat:  [ Transcript show: 'x' ]. Transcript showOnDisplay: true ]. 1.
        "As fast as Pharo"

It is also thread safe, and for Ben's example:

Transcript clear.
[
        $a asciiValue to: $z asciiValue do: [ :c |
                [ 1 to: 9 do: [ :i | Transcript show: c asCharacter printString , i printString , ' ' ] ] forkAt: 40
        ].
] forkAt: 41

it gives the same result as Pharo.

The fact that the updates are not bound to Morphic also means that it is possible to do #show: deep in Morphic logic, without causing infinite loops or recursions, and get immediate feedback. It has proved to be a useful aid in debugging Morphic code.

Cheers,
Juan Vuletich

--

best,

Eliot

--

www.tudorgirba.com

"Every thing has its own flow"

Hi Tudor,

On Sat, May 9, 2015 at 2:23 PM, Tudor Girba <[hidden email]> wrote:

Hi Eliot,

Just a question: Could you describe the situations when you need to have the Transcript editable?

I am not trying to provoke you,

my reputation preceeds me ;-)

 

but to understand use cases. While working on GT I found that it is often possible to support the same use cases with multiple UI solutions. And sometimes considering alternatives leads to interesting results.

While I have an over-full transcript that holds progress over time, notes etc, these could be moved to a workspace.  What I really use editablity in the transcript for is to cut-down output.  For example, if I'm analysing some jitted code it will get printed out in the transcript (without a lot of retooling) and it is very convenient to cut down the often large amount of output to focus on what I'm interested in.  Or I might be trying to fix a bug with repeated runs and again collect relevant data (print outs of objects or stack frames from the simulator) for use as reference points in later runs.  Or I might collect some warnings from the Slang SMalltalk-to-C translator.

In short, there's a lot of different kinds of data going to the transcript and it can be useful to edit it in place instead of having to copy it elsewhere.

Cheers,

Doru

On Sat, May 9, 2015 at 9:32 PM, Eliot Miranda <[hidden email]> wrote:

Hi Juan,

    I see that your new transcript is indeed much faster but is also not editable.  I wonder if it would be possible to have the best of both worlds and arrange that, when active, the transcript is editable.  For example, selecting the TranscriptWIndow could put it into a mode where the transcript's state was imported into a more conventional editable text morph, and then when the window was exited, reverted to the standard fast output mode.  As you can infer I like having an editable transcript.  I can do without it, because Squeak's slow transcript is indeed a PITA, but I'm not sure that speed need preclude editability.

On Sat, May 9, 2015 at 10:17 AM, J. Vuletich (mail lists) <[hidden email]> wrote:

Hi Folks,

(below)

Quoting Ben Coman <[hidden email]>:

On Sat, May 9, 2015 at 10:35 PM, Eliot Miranda <[hidden email]>
wrote:

On Sat, May 9, 2015 at 7:09 AM, Ben Coman <[hidden email]> wrote:

From my limited experience bug hunting, calling #changed: from a thread
other than the UI thread is a source of evil.  There are too many
assumptions throughout the system that the UI is single threaded.  Can
anyone advise me that is not a proper belief?

Then that implies that a Transcript implementation where #nextPut: direct
calls #changed:
is not appropriate for use with multi-threaded applications.  In Pharo,
#changed: is only called from #stepGlobal, which is called from
doOneCycle:.  (This came about as a last minute bug fix before Pharo 3
release and maybe could use some cleanup.

Separating the UI from Transcript into its own viewer might be a good
idea, but actually it would not solve Stef's case since his code would
still be running in the UI thread -- unless the viewer ran in another
thread, which would have its own complexities.

I think the point about efficiency is significant. The following
example...
     Time millisecondsToRun: [ 1000 timesRepeat:  [ Transcript show: 'x'
] ]
on Squeak 4.5 --> 12749ms
on Pharo 50029 --> 2ms

This better performance helped me a lot trying to understand the high
priority timerEventLoop being able to indiscriminately scatter Transcript
tracing through that code.  I believe its also probably beneficial for
working with externally triggered semaphores and timing sensitive race
conditions.

So we have two mutually exclusive cases:
* better interactivity, poorer system performance
* faster system performance, worse interactivity

Which of these is broken depends on your viewpoint.

Something that runs fast but is incorrect is still incorrect.  The fact
that the transcript doesn't output until a world step is possible is a
bug.  It forces programs that use the transcript to be rewritten in order
to see transcript output.

As a point of comparison for correctness, for the following...

    Transcript clear.
    [   $a asciiValue to: $z asciiValue do: [ :c |
  [ 1 to: 9 do: [ :i | Transcript show: c asCharacter printString , i
printString , ' ' ] ] forkAt: 40
].
    ] forkAt: 41

Squeak 4.5 gives...
$a1 $a2 $a3 $a4 $a5 $a6 $a7 $a8 $a9 $b1 $b2 $b3 $b4 $b5 $b5 $c1 $c2 $c3 $c4
$c5 $c6 $c7 $c8 $c9 $d1 $d2 $d3 $d4 $d5 $d6 $d7 $d8 $d9 $d9 $e2 $g2 $h2 $h2
$i2 $k2 $k2 $l2 $n2 $n2 $o2 $o2 $r2 $s2 $t2 $u2 $u2 $v2 $x2 $y2 $z2 $z2 $b7
$f3 $e3 $e3 $g3 $j3 $h3 $i3 $k3 $k3 $m3 $n3 $p3 $p3 $q3 $o3 $s3 $t3 $t3 $u3
$v3 $x3 $y3 $z3 $b8 $f4 $e4 $e4 $g4 $h4 $i4 $k4 $l4 $m4 $m4 $n4 $r4 $q4 $o4
$o4 $s4 $w4 $u4 $u4 $v4 $y4 $y4 $z4 $z4 $f5 $j5 $j5 $g5 $i5 $k5 $l5 $l5 $m5
$m5 $n5 $q5 $o5 $s5 $s5 $t5 $u5 $u5 $x5 $y5 $z5 $f6 $f6 $h6 $h6 $g6 $g6 $k6
$p6 $m6 $r6 $r6 $n6 $o6 $s6 $s6 $w6 $u6 $x6 $x6 $e7 $f7 $j7 $h7 $h7 $i7 $l7
$l7 $k7 $m7 $m7 $q7 $n7 $n7 $o7 $t7 $w7 $w7 $u7 $v7 $x7 $z7 $z7 $e8 $e8 $h8
$g8 $i8 $i8 $l8 $k8 $k8 $m8 $q8 $n8 $n8 $s8 $t8 $w8 $y8 $y8 $u8 $x8 $z8 $f9
$f9 $e9 $h9 $h9 $g9 $p9 $p9 $k9 $r9 $r9 $m9 $n9 $n9 $o9 $t9 $t9 $w9 $v9 $u9
$u9 $z9 $x9

Pharo 50041 gives...
$a1 $a2 $a3 $a4 $a5 $a6 $a7 $a8 $a9 $b1 $b2 $b3 $b4 $b5 $b6 $b7 $b8 $b9 $c1
$c2 $c3 $c4 $c5 $c6 $c7 $c8 $c9 $d1 $d2 $d3 $d4 $d5 $d6 $d7 $d8 $d9 $e1 $e2
$e3 $e4 $e5 $e6 $e7 $e8 $e9 $f1 $f2 $f3 $f4 $f5 $f6 $f7 $f8 $f9 $g1 $g2 $g3
$g4 $g5 $g6 $g7 $g8 $g9 $h1 $h2 $h3 $h4 $h5 $h6 $h7 $h8 $h9 $i1 $i2 $i3 $i4
$i5 $i6 $i7 $i8 $i9 $j1 $j2 $j3 $j4 $j5 $j6 $j7 $j8 $j9 $k1 $k2 $k3 $k4 $k5
$k6 $k7 $k8 $k9 $l1 $l2 $l3 $l4 $l5 $l6 $l7 $l8 $l9 $m1 $m2 $m3 $m4 $m5 $m6
$m7 $m8 $m9 $n1 $n2 $n3 $n4 $n5 $n6 $n7 $n8 $n9 $o1 $o2 $o3 $o4 $o5 $o6 $o7
$o8 $o9 $p1 $p2 $p3 $p4 $p5 $p6 $p7 $p8 $p9 $q1 $q2 $q3 $q4 $q5 $q6 $q7 $q8
$q9 $r1 $r2 $r3 $r4 $r5 $r6 $r7 $r8 $r9 $s1 $s2 $s3 $s4 $s5 $s6 $s7 $s8 $s9
$t1 $t2 $t3 $t4 $t5 $t6 $t7 $t8 $t9 $u1 $u2 $u3 $u4 $u5 $u6 $u7 $u8 $u9 $v1
$v2 $v3 $v4 $v5 $v6 $v7 $v8 $v9 $w1 $w2 $w3 $w4 $w5 $w6 $w7 $w8 $w9 $x1 $x2
$x3 $x4 $x5 $x6 $x7 $x8 $x9 $y1 $y2 $y3 $y4 $y5 $y6 $y7 $y8 $y9 $z1 $z2 $z3
$z4 $z5 $z6 $z7 $z8 $z9

(start your comparison at $b5)

So in one axis Pharo has improved Transcript, but we didn't notice the
significance of the use case we lost.

cheers -ben

Please take a good look at Cuis' Transcript and consider using it.

By default, the display is updated immediately, but without calling Morphic, it can even work with no UI framework at all. It does updates faster than Squeak or Visualworks:

        Time millisecondsToRun: [ 1000 timesRepeat:  [ Transcript show: 'x' ] ]. 763.

But if you want minimum overhead without immediate feedback:

        Time millisecondsToRun: [ Transcript showOnDisplay: false. 1000 timesRepeat:  [ Transcript show: 'x' ]. Transcript showOnDisplay: true ]. 1.
        "As fast as Pharo"

It is also thread safe, and for Ben's example:

Transcript clear.
[
        $a asciiValue to: $z asciiValue do: [ :c |
                [ 1 to: 9 do: [ :i | Transcript show: c asCharacter printString , i printString , ' ' ] ] forkAt: 40
        ].
] forkAt: 41

it gives the same result as Pharo.

The fact that the updates are not bound to Morphic also means that it is possible to do #show: deep in Morphic logic, without causing infinite loops or recursions, and get immediate feedback. It has proved to be a useful aid in debugging Morphic code.

Cheers,
Juan Vuletich

--

best,

Eliot

--

www.tudorgirba.com

"Every thing has its own flow"

--

best,

Eliot