Splitting up 27_io/basic_istream/ignore/wchar_t/94749.cc (takes too long)

Splitting up 27_io/basic_istream/ignore/wchar_t/94749.cc (takes too long)

[Hans-Peter Nilsson]

Hi!

The test 27_io/basic_istream/ignore/wchar_t/94749.cc takes
about 10 minutes to run for cris-elf in the "gdb simulator"
here on my arguably way-past-retirement machine (and it
looks like it gained a minute with LRA).  I've seen it
timing out every now and then on busy days with load >
`nproc`.  Usually it happens some time after I've forgot
about why. :)

It has had some performance surgery before (pruning for
simulators, doubling timeout for ilp32).  I'd probably just
try cutting along the function boundaries and keep those
parts separate that have >1 min execution time.

Anyway, your thoughts on the matter would be appreciated.

brgds, H-P

Re: Splitting up 27_io/basic_istream/ignore/wchar_t/94749.cc (takes too long)

[Mike Stump]

On Jun 9, 2023, at 9:20 AM, Hans-Peter Nilsson via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
> 
> The test 27_io/basic_istream/ignore/wchar_t/94749.cc takes
> about 10 minutes to run for cris-elf in the "gdb simulator"

I'd let the libstdc++ people comment on specific things.  I'll comment on general things.  We could let line count (or word count or character count) scale the timeout in part, we could record times in a db and put an expected run time into test cases or in an along side db. We could have factors for slow systems, slow simulators. A 5 GHz x86_64 will likely be faster that a 40 year old pdp11. We can have these scale factors trigger off OS, cpu statically, and/or we can do a quick bogomips calculation and let that scale it and record that scaling factor in the build tree.

A wealth of possibilities. Solutions that require maintenance or test case modification are annoying. Solutions that need port work are annoying. I'd be tempted to say bogomips into the build (test) tree.  There are two parts, time to compile test cases and time to run them.  I'd be fine with a half solution that only does what you need.  The other part can be done by someone that has a need.

I'd invite comments by others on other solutions or commentary on downsides.  For example, having a 208 thread count machine that takes 2-3 minutes to run the full testsuite is nice. A problem arises when 4-10 test cases suddenly start timing out.  You then go to around 10-53 minutes to test, which  is annoying. Anything that boosts the timeouts can hinder early port bring up, which, we'd like to avoid. I mention it without much a solution other than a db approach in the test tree that records each test case and can identify test cases that timeout and trim the timeout for them to something nicer like base + 50% once they timeout with a larger allotment of time.

We could entertain wild thoughts. For example, make a run cache that caches run results given an object. See an object in the future, just look it up in a hash cache for the object and return those results instead of running it.  This can give you a large speedup in testing and would simultaneously advantage all slow simulation ports.  Maybe a 20-100x speedup? If you want to go this way I'd say do it in python at the bottom as it would be nice to switch over to python in the next 5-20 years and away from tcl.

A object cache in python, should be fairly small wether it is used for remembering run times from previous runs and setting a timeout based upon it, or as a does it run  and pass or run and fail cache.  The caches are likely only part of the problem, one still needs to have a timeout when no cache entry it present.  They can speed testing for the day to day grind of people that run 1-200 times a week.

Re: Splitting up 27_io/basic_istream/ignore/wchar_t/94749.cc (takes too long)

[Hans-Peter Nilsson]

> From: Mike Stump <mikestump@comcast.net>
> Date: Fri, 9 Jun 2023 10:18:45 -0700

> On Jun 9, 2023, at 9:20 AM, Hans-Peter Nilsson via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
> > 
> > The test 27_io/basic_istream/ignore/wchar_t/94749.cc takes
> > about 10 minutes to run for cris-elf in the "gdb simulator"
> 
> I'd let the libstdc++ people comment on specific things.
> I'll comment on general things.  We could let line count
> (or word count or character count) scale the timeout in
> part, we could record times in a db and put an expected
> run time into test cases or in an along side db. We could
> have factors for slow systems, slow simulators. A 5 GHz
> x86_64 will likely be faster that a 40 year old pdp11. We
> can have these scale factors trigger off OS, cpu
> statically, and/or we can do a quick bogomips calculation
> and let that scale it and record that scaling factor in
> the build tree.

Wild plans, but with some points.

Beware that uniform testing IMO weighs in much heavier than
uniform test-time.  Like, arm-eabi, rv32-elf and cris-elf,
having common main factors, should test the same code and
the same number of iterations, preferably regardless of
simulator quality.  (FWIW, I consider the cris-elf gdb
simulator is *fast* - before 2021 or when built
--disable-sim-hardware.)

> A wealth of possibilities.

And complexity!

> Solutions that require maintenance or test case
> modification are annoying.

Yeah, but that maintenance annoyance unfortunately includes
initial setup.  You propose quite a major shift there.  It
sounds good, but sorry, but I must settle for just editing
the test-case some way.

brgds, H-P

Re: Splitting up 27_io/basic_istream/ignore/wchar_t/94749.cc (takes too long)

[Jonathan Wakely]

[-- Attachment #1.1: Type: text/plain, Size: 2628 bytes --]

On Fri, 9 Jun 2023 at 17:20, Hans-Peter Nilsson <hp@axis.com> wrote:

> Hi!
>
> The test 27_io/basic_istream/ignore/wchar_t/94749.cc takes
> about 10 minutes to run for cris-elf in the "gdb simulator"
> here on my arguably way-past-retirement machine (and it
> looks like it gained a minute with LRA).  I've seen it
> timing out every now and then on busy days with load >
> `nproc`.  Usually it happens some time after I've forgot
> about why. :)
>
> It has had some performance surgery before (pruning for
> simulators, doubling timeout for ilp32).  I'd probably just
> try cutting along the function boundaries and keep those
> parts separate that have >1 min execution time.
>

test01, test02, test03 and test04 should run almost instantly. On my system
they take about 5 microseconds each. So I don't think splitting those up
will help.

test05 extracts INT_MAX characters from a stream, which is a LOT of work.
It doesn't actually read those from a file, the "stream" is a custom
streambuf that contains a buffer of millions of wchar_t and "reading" from
the stream just increments a counter into that buffer. But we do have to
allocate memory for that buffer and then zero-init that buffer. That's a
lot of cycles. Then once we've done that, we need to keep looping until we
overflow a 32-bit counter (we don't increment by 1 every loop, so it
overflows pretty quickly).

Then we do it again and again and again! Each time takes about half a
second for me.

I thought it would help to avoid re-allocating the buffer and zeroing it
again. If we reuse the same buffer, then we just have to loop until we
overflow the 32-bit counter. That would make the whole test run much
faster, which would reduce the total time for a testsuite run. Splitting
the file up into smaller files would not decrease the total time, only
decrease the time for that single test so it doesn't time out.

I've attached a patch that does that. I makes very little difference for
me, probably because allocating zero-filled pages isn't actually expensive
on linux. Maybe it will make a differene for your simulator though?

You could also try reducing the size of the buffer:
+#ifdef SIMULATOR_TEST
+  static const streamsize bufsz = 16 << limits::digits10;
+#else
  static const streamsize bufsz = 2048 << limits::digits10;
+#endif

test06 is the really slow part, that takes 10+ seconds for me. But that
entire function should already be skipped for simulators.

We can probably skip test05 for simulators too, none of the code it tests
is platform-specific, so as long as it's being tested on x86 we don't
really need to test it on cris-elf too.

[-- Attachment #2: patch.txt --]
[-- Type: text/plain, Size: 3909 bytes --]

diff --git a/libstdc++-v3/testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc b/libstdc++-v3/testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc
index 65e0a326c10..040e94aa4d6 100644
--- a/libstdc++-v3/testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc
+++ b/libstdc++-v3/testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc
@@ -89,7 +89,7 @@ struct buff : std::basic_streambuf<typename T::char_type, T>
   typedef std::streamsize		  streamsize;
   typedef std::numeric_limits<streamsize> limits;
 
-  buff() : count(0), buf() { }
+  buff() : count(0), nonzero_chars(), buf() { }
 
   int_type underflow()
   {
@@ -112,12 +112,23 @@ struct buff : std::basic_streambuf<typename T::char_type, T>
       buf[headroom+1] = L'3';
       this->setg(buf, buf, buf + headroom + 2);
       count = limits::max();
+      nonzero_chars = headroom - 1;
     }
 
     return buf[0];
   }
 
+  void reset()
+  {
+    buf[nonzero_chars] = char_type();
+    buf[nonzero_chars+1] = char_type();
+    buf[nonzero_chars+2] = char_type();
+    nonzero_chars = 0;
+    count = 0;
+  }
+
   streamsize count;
+  streamsize nonzero_chars;
 
   static const streamsize bufsz = 2048 << limits::digits10;
   char_type buf[bufsz + 2];
@@ -132,7 +143,8 @@ test05()
 
   typedef std::char_traits<C> T;
 
-  std::basic_istream<C, T> in(new buff<T>);
+  buff<T>* pbuf = new buff<T>;
+  std::basic_istream<C, T> in(pbuf);
 
   in.ignore(std::numeric_limits<std::streamsize>::max(), L'1');
   VERIFY(in.good());
@@ -141,7 +153,9 @@ test05()
   VERIFY(in.get() == L'3');
   VERIFY(in.get() == T::eof());
 
-  delete in.rdbuf(new buff<T>);
+  pbuf->reset();
+  in.clear();
+  VERIFY(in.gcount() == 0);
 
   in.ignore(std::numeric_limits<std::streamsize>::max(), L'2');
   VERIFY(in.good());
@@ -150,7 +164,9 @@ test05()
   VERIFY(in.get() == L'3');
   VERIFY(in.get() == T::eof());
 
-  delete in.rdbuf(new buff<T>);
+  pbuf->reset();
+  in.clear();
+  VERIFY(in.gcount() == 0);
 
   in.ignore(std::numeric_limits<std::streamsize>::max(), L'3');
   VERIFY(in.good());
@@ -158,7 +174,9 @@ test05()
   VERIFY(in.gcount() == std::numeric_limits<std::streamsize>::max());
   VERIFY(in.get() == T::eof());
 
-  delete in.rdbuf(new buff<T>);
+  pbuf->reset();
+  in.clear();
+  VERIFY(in.gcount() == 0);
 
   in.ignore(std::numeric_limits<std::streamsize>::max(), L'4');
   VERIFY(in.eof());
@@ -166,7 +184,8 @@ test05()
   VERIFY(in.gcount() == std::numeric_limits<std::streamsize>::max());
   VERIFY(in.get() == T::eof());
 
-  delete in.rdbuf(0);
+  in.rdbuf(0);
+  delete pbuf;
 }
 
 void
@@ -177,7 +196,8 @@ test06()
 
   typedef __gnu_cxx::char_traits<C> T;
 
-  std::basic_istream<C, T> in(new buff<T>);
+  buff<T>* pbuf = new buff<T>;
+  std::basic_istream<C, T> in(pbuf);
 
   in.ignore(std::numeric_limits<std::streamsize>::max(), L'1');
   VERIFY(in.good());
@@ -186,7 +206,9 @@ test06()
   VERIFY(in.get() == L'3');
   VERIFY(in.get() == T::eof());
 
-  delete in.rdbuf(new buff<T>);
+  pbuf->reset();
+  in.clear();
+  VERIFY(in.gcount() == 0);
 
   in.ignore(std::numeric_limits<std::streamsize>::max(), L'2');
   VERIFY(in.good());
@@ -195,7 +217,9 @@ test06()
   VERIFY(in.get() == L'3');
   VERIFY(in.get() == T::eof());
 
-  delete in.rdbuf(new buff<T>);
+  pbuf->reset();
+  in.clear();
+  VERIFY(in.gcount() == 0);
 
   in.ignore(std::numeric_limits<std::streamsize>::max(), L'3');
   VERIFY(in.good());
@@ -203,7 +227,9 @@ test06()
   VERIFY(in.gcount() == std::numeric_limits<std::streamsize>::max());
   VERIFY(in.get() == T::eof());
 
-  delete in.rdbuf(new buff<T>);
+  pbuf->reset();
+  in.clear();
+  VERIFY(in.gcount() == 0);
 
   in.ignore(std::numeric_limits<std::streamsize>::max(), L'4');
   VERIFY(in.eof());
@@ -211,7 +237,8 @@ test06()
   VERIFY(in.gcount() == std::numeric_limits<std::streamsize>::max());
   VERIFY(in.get() == T::eof());
 
-  delete in.rdbuf(0);
+  in.rdbuf(0);
+  delete pbuf;
 }
 
 int

Re: Splitting up 27_io/basic_istream/ignore/wchar_t/94749.cc (takes too long)

[Bernhard Reutner-Fischer]

On 9 June 2023 19:18:45 CEST, Mike Stump via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
> simulation ports.  Maybe a 20-100x speedup? If you want to go this way I'd say do it in python at the bottom as it would be nice to switch over to python in the next 5-20 years and away from tcl.

Yes, i guess we have all pondered this for way long enough, but it is a lot of work still.

The nice side effect would be that we see such hogs easier and earlier, at least more comfortable. But well. Either way, what should we do about remote env, if there is one? If the target supports it, send it and skip otherwise?

thanks,

[PATCH] (Re: Splitting up 27_io/basic_istream/ignore/wchar_t/94749.cc (takes too long))

[Hans-Peter Nilsson]

Thank you for your consideration.  (Or is that phrase only used negatively?)

> From: Jonathan Wakely <jwakely@redhat.com>
> Date: Fri, 9 Jun 2023 21:40:15 +0100

> test01, test02, test03 and test04 should run almost instantly. On my system
> they take about 5 microseconds each. So I don't think splitting those up
> will help.

Right.

> I thought it would help to avoid re-allocating the buffer and zeroing it
> again. If we reuse the same buffer, then we just have to loop until we
> overflow the 32-bit counter. That would make the whole test run much
> faster, which would reduce the total time for a testsuite run. Splitting
> the file up into smaller files would not decrease the total time, only
> decrease the time for that single test so it doesn't time out.
> 
> I've attached a patch that does that. I makes very little difference for
> me, probably because allocating zero-filled pages isn't actually expensive
> on linux. Maybe it will make a differene for your simulator though?

Nope, just some five seconds down (from about 10min 21s).

> You could also try reducing the size of the buffer:
> +#ifdef SIMULATOR_TEST
> +  static const streamsize bufsz = 16 << limits::digits10;
> +#else
>   static const streamsize bufsz = 2048 << limits::digits10;
> +#endif

Was that supposed to be with or without the patch?  Anyway;
both: 606s.  Only smaller bufsz: 614s.  (All numbers subject
to usual system jitter.)

> test06 is the really slow part, that takes 10+ seconds for me. But that
> entire function should already be skipped for simulators.

Yep, we may have been here before...  I certainly get a
deja-vu feeling here, but visiting old email conversations
of ours, it seems I easily conflate several similar ones.
I see that here, test06 was always #ifndef SIMULATOR_TEST.

> We can probably skip test05 for simulators too, none of the code it tests
> is platform-specific, so as long as it's being tested on x86 we don't
> really need to test it on cris-elf too.

Thanks.  Let's do that, then.  The similar s/wchar_t/char/
test clocks in at "only" 3m30s, but I suggest treating it
the same, if nothing else than for symmetry.

Ok as below?

-- >8 --
Subject: [PATCH] testsuite: Cut down 27_io/basic_istream/.../94749.cc for
 simulators

The test wchar_t/94749.cc can take about 10 minutes on some
simulator/host combinations with char/94749.cc at a third of
that time.  The cause is test05 which is quite heavy and
includes wrapping a 32-bit counter.  Run it only for native
setups.

	* testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc (main)
	[! SIMULATOR_TEST]: Also exclude running test05.
	* testsuite/27_io/basic_istream/ignore/char/94749.cc: Ditto.
---
 libstdc++-v3/testsuite/27_io/basic_istream/ignore/char/94749.cc | 2 +-
 .../testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc       | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/libstdc++-v3/testsuite/27_io/basic_istream/ignore/char/94749.cc b/libstdc++-v3/testsuite/27_io/basic_istream/ignore/char/94749.cc
index 6416863983b7..9160995c05ec 100644
--- a/libstdc++-v3/testsuite/27_io/basic_istream/ignore/char/94749.cc
+++ b/libstdc++-v3/testsuite/27_io/basic_istream/ignore/char/94749.cc
@@ -221,8 +221,8 @@ main()
   test02();
   test03();
   test04();
-  test05();
 #ifndef SIMULATOR_TEST
+  test05();
   test06();
 #endif
 }
diff --git a/libstdc++-v3/testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc b/libstdc++-v3/testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc
index 65e0a326c109..a5b9eb71a389 100644
--- a/libstdc++-v3/testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc
+++ b/libstdc++-v3/testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc
@@ -221,8 +221,8 @@ main()
   test02();
   test03();
   test04();
-  test05();
 #ifndef SIMULATOR_TEST
+  test05();
   test06();
 #endif
 }
-- 
2.30.2

Re: [PATCH] (Re: Splitting up 27_io/basic_istream/ignore/wchar_t/94749.cc (takes too long))

[Jonathan Wakely]

[-- Attachment #1: Type: text/plain, Size: 4218 bytes --]

On Sat, 10 Jun 2023, 06:18 Hans-Peter Nilsson via Libstdc++, <
libstdc++@gcc.gnu.org> wrote:

> Thank you for your consideration.  (Or is that phrase only used
> negatively?)
>
> > From: Jonathan Wakely <jwakely@redhat.com>
> > Date: Fri, 9 Jun 2023 21:40:15 +0100
>
> > test01, test02, test03 and test04 should run almost instantly. On my
> system
> > they take about 5 microseconds each. So I don't think splitting those up
> > will help.
>
> Right.
>
> > I thought it would help to avoid re-allocating the buffer and zeroing it
> > again. If we reuse the same buffer, then we just have to loop until we
> > overflow the 32-bit counter. That would make the whole test run much
> > faster, which would reduce the total time for a testsuite run. Splitting
> > the file up into smaller files would not decrease the total time, only
> > decrease the time for that single test so it doesn't time out.
> >
> > I've attached a patch that does that. I makes very little difference for
> > me, probably because allocating zero-filled pages isn't actually
> expensive
> > on linux. Maybe it will make a differene for your simulator though?
>
> Nope, just some five seconds down (from about 10min 21s).
>

Bah, worth a try :)


> > You could also try reducing the size of the buffer:
> > +#ifdef SIMULATOR_TEST
> > +  static const streamsize bufsz = 16 << limits::digits10;
> > +#else
> >   static const streamsize bufsz = 2048 << limits::digits10;
> > +#endif
>
> Was that supposed to be with or without the patch?  Anyway;
> both: 606s.  Only smaller bufsz: 614s.  (All numbers subject
> to usual system jitter.)
>
> > test06 is the really slow part, that takes 10+ seconds for me. But that
> > entire function should already be skipped for simulators.
>
> Yep, we may have been here before...  I certainly get a
> deja-vu feeling here, but visiting old email conversations
> of ours, it seems I easily conflate several similar ones.
> I see that here, test06 was always #ifndef SIMULATOR_TEST.
>
> > We can probably skip test05 for simulators too, none of the code it tests
> > is platform-specific, so as long as it's being tested on x86 we don't
> > really need to test it on cris-elf too.
>
> Thanks.  Let's do that, then.  The similar s/wchar_t/char/
> test clocks in at "only" 3m30s, but I suggest treating it
> the same, if nothing else than for symmetry.
>
> Ok as below?
>

OK for trunk, and all branches you care about.



> -- >8 --
> Subject: [PATCH] testsuite: Cut down 27_io/basic_istream/.../94749.cc for
>  simulators
>
> The test wchar_t/94749.cc can take about 10 minutes on some
> simulator/host combinations with char/94749.cc at a third of
> that time.  The cause is test05 which is quite heavy and
> includes wrapping a 32-bit counter.  Run it only for native
> setups.
>
>         * testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc (main)
>         [! SIMULATOR_TEST]: Also exclude running test05.
>         * testsuite/27_io/basic_istream/ignore/char/94749.cc: Ditto.
> ---
>  libstdc++-v3/testsuite/27_io/basic_istream/ignore/char/94749.cc | 2 +-
>  .../testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc       | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git
> a/libstdc++-v3/testsuite/27_io/basic_istream/ignore/char/94749.cc
> b/libstdc++-v3/testsuite/27_io/basic_istream/ignore/char/94749.cc
> index 6416863983b7..9160995c05ec 100644
> --- a/libstdc++-v3/testsuite/27_io/basic_istream/ignore/char/94749.cc
> +++ b/libstdc++-v3/testsuite/27_io/basic_istream/ignore/char/94749.cc
> @@ -221,8 +221,8 @@ main()
>    test02();
>    test03();
>    test04();
> -  test05();
>  #ifndef SIMULATOR_TEST
> +  test05();
>    test06();
>  #endif
>  }
> diff --git
> a/libstdc++-v3/testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc
> b/libstdc++-v3/testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc
> index 65e0a326c109..a5b9eb71a389 100644
> --- a/libstdc++-v3/testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc
> +++ b/libstdc++-v3/testsuite/27_io/basic_istream/ignore/wchar_t/94749.cc
> @@ -221,8 +221,8 @@ main()
>    test02();
>    test03();
>    test04();
> -  test05();
>  #ifndef SIMULATOR_TEST
> +  test05();
>    test06();
>  #endif
>  }
> --
> 2.30.2
>
>

Re: Splitting up 27_io/basic_istream/ignore/wchar_t/94749.cc (takes too long)

[Mike Stump]

On Jun 9, 2023, at 2:47 PM, Bernhard Reutner-Fischer <rep.dot.nop@gmail.com> wrote:
> 
> On 9 June 2023 19:18:45 CEST, Mike Stump via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
>> simulation ports.  Maybe a 20-100x speedup? If you want to go this way I'd say do it in python at the bottom as it would be nice to switch over to python in the next 5-20 years and away from tcl.
> 
> Yes, i guess we have all pondered this for way long enough, but it is a lot of work still.
> 
> The nice side effect would be that we see such hogs easier and earlier, at least more comfortable. But well. Either way, what should we do about remote env, if there is one? If the target supports it, send it and skip otherwise?

Testing is a large barrel of monkeys with a ton of small points, each of which is critical in some one. It is hard to talk about generalities when those details are very specific.  So, to focus a conversation, which target, which host, canadian? Which part of the environment? What part is missing you want to fix? Want to unify between targets... and so on.

Re: Splitting up 27_io/basic_istream/ignore/wchar_t/94749.cc (takes too long)

[Bernhard Reutner-Fischer]

On Sat, 10 Jun 2023 11:29:36 -0700
Mike Stump <mikestump@comcast.net> wrote:

> On Jun 9, 2023, at 2:47 PM, Bernhard Reutner-Fischer
> <rep.dot.nop@gmail.com> wrote:

> >                                     But well. Either way, what
> > should we do about remote env, if there is one? If the target
> > supports it, send it and skip otherwise?  

> So, to focus a
> conversation, which target, which host, canadian? Which part of the
> environment? What part is missing you want to fix? Want to unify
> between targets... and so on.
> 

The most recent target where this came up again was GCN i think.
See the last block in
https://inbox.sourceware.org/gcc-patches/20230508195217.4897009f@nbbrfq/
and Thomas' reference therein to Tobias'
https://inbox.sourceware.org/gcc-patches/018bcdeb-b3bb-1859-cd0b-a8a92e26d3a0@codesourcery.com/

thoughts?

thanks,

Re: Splitting up 27_io/basic_istream/ignore/wchar_t/94749.cc (takes too long)

[Mike Stump]

On Jun 12, 2023, at 1:35 AM, Bernhard Reutner-Fischer <rep.dot.nop@gmail.com> wrote:
> 
> On Sat, 10 Jun 2023 11:29:36 -0700
> Mike Stump <mikestump@comcast.net> wrote:
> 
>> On Jun 9, 2023, at 2:47 PM, Bernhard Reutner-Fischer
>> <rep.dot.nop@gmail.com> wrote:
> 
>>>                                    But well. Either way, what
>>> should we do about remote env, if there is one? If the target
>>> supports it, send it and skip otherwise?  
> 
>> So, to focus a
>> conversation, which target, which host, canadian? Which part of the
>> environment? What part is missing you want to fix? Want to unify
>> between targets... and so on.
>> 
> 
> The most recent target where this came up again was GCN i think.
> See the last block in
> https://inbox.sourceware.org/gcc-patches/20230508195217.4897009f@nbbrfq/
> and Thomas' reference therein to Tobias'
> https://inbox.sourceware.org/gcc-patches/018bcdeb-b3bb-1859-cd0b-a8a92e26d3a0@codesourcery.com/
> 
> thoughts?

I kinds like the remote_setenv approach, but the low level details when one gets in there and wires up all they need to make it work are important.

If someone wants to tilt at the problem, I'm inclined to let them find the incantation they like and approve it.

I'd rather approve a patch that takes us a step closer to perfection then go another 10 years.  For quoting. I like quite using ' if there is no ' in the string.  For each ' in the string, replace it with '\'', inelegant, but easier to reason about and don't have to worry about as many meta characters if you try and go the "" route.

This assumes something like sh is taking in commands.  This isn't always the case.  One can canadian into a windows box or some other weird thing so the mechanism used has to be next to the thing that knows what it is talking to.

Just because someone contributes code for talking to sh, doesn't mean they have to bother with windows or other weird stuff.  The next person to come along can tilt at that.