System getting stuck by GCC invocation

[Thomas Schwinge]

Hi!

Here is a test case that gets a Hurd system "stuck".  (But I don't know
yet what "stuck" exactly means.)  Unfortunately, the test case is a
biggie: GCC.  The steps to reproduce it, reduced as much as I could:

Fetch GCC trunk, for example retrieve the following snapshot:
,
or a Subversion or Git checkout: r215404 or commit
20a52496a54ae8916e2bfc4d38aec95bb3592242, respectively, is what I've been
using.

$ mkdir trunk.build && cd trunk.build/
$ ../trunk/configure --prefix=$PWD.install --enable-languages=java 
--disable-bootstrap --with-native-system-header-dir=/usr/include 
--enable-multiarch --enable-link-mutex --disable-lto --disable-libcilkrts 
--disable-libgomp
[...]
$ make -j2 configure-target-libjava
[Takes some time, produce more than 1 GiB of "stuff".]
$ make -C i686-unknown-gnu0.5/libjava/classpath/lib/ classes
[...]
$ \time make -C i686-unknown-gnu0.5/libjava/ gnu/java/nio/charset.lo
/bin/sh ./libtool --tag=GCJ   --mode=compile [...]
libtool: compile:  /home/thomas/tmp/gcc/trunk.build/./gcc/gcj [...] -o 
gnu/java/nio/.libs/charset.o

The last one, the gcj invocation, is the command to bring down the
system.  You can further decompose that one: cd to
i686-unknown-gnu0.5/libjava/, and in there run the »[...]/gcj [...]«
command with »-v -save-temps« added, then you'll see:

[...]
 /home/thomas/tmp/gcc/trunk.build/./gcc/jc1 /tmp/cc[...] -o cc[...].s
GNU Java (GCC) version 5.0.0 20140919 [...]

That jc1 invocation (which does not fork further, so can be rpctraced and
all that) basically takes a number of Java class files, and writes those
into cc[...].s, 160 MiB of "assembler" source code.  (When runnign under
rpctrace, this can be observed, and the process terminates normally.)  If
the system doesn't get stuck before, this assembler source file will then
be further processed into an object file of 24 MiB.  Running that last
»\time make [...]« command line on x86 Debian GNU/Linux:

74.77user 2.58system 1:22.38elapsed 93%CPU (0avgtext+0avgdata 
488804maxresident)k
152inputs+375640outputs (0major+206659minor)pagefaults 0swaps

So, that had a RSS of about 500 MiB as well as considerable CPU time
usage.  On the Hurd we additionally have to deal with the memory
management for the many out-of-line RPC buffers for the data that is
being sent between the processes.

Running »vmstat 1« in parallel, one can see the free memory decrease and
inactive increase, and when the system gets stuck, there is still plenty
of free memory available (for example, 780 MiB), and vmstat keeps
updating (but the delta between the values it prints gets next to zero),
but the gcj process was already stuck, couldn't be SIGINTed, and no
further shells could be spawned, and so on.

This testing was done in a QEMU/KVM Hurd system, configured with 1536 GiB
of RAM.  Some time after beginning to execute the jc1 command, the system
stops responding, but still consumes 100 % host CPU time.  And, if QEMU's
built-in gdbserver is to be believed, it is still doing "something":

(gdb) target remote :1234
Remote debugging using :1234
0x801094d7 in spl0 () at ../i386/i386/spl.S:106
106 SETMASK()   /* program PICs with new 
mask */
(gdb) bt
#0  0x801094d7 in spl0 () at ../i386/i386/spl.S:106
#1  0x0007 in ?? ()
#2  0x80127880 in thread_depress_abort (thread=0xe19eabe0) at 
../kern/syscall_subr.c:381
#3  0x801278c7 in thread_depress_abort (thread=) at 
../kern/syscall_subr.c:102
#4  swtch_pri_continue () at ../kern/syscall_subr.c:103
#5  0x in ?? ()
(gdb) c
Continuing.
^C
Program received signal SIGINT, Interrupt.
spl0 () at ../i386/i386/spl.S:108
108 sti /* enable interrupts */
(gdb) bt
#0  spl0 () at ../i386/i386/spl.S:108
#1  0x0007 in ?? ()
#2  0x801279ef in thread_depress_priority (thread=0xe19eabe0, 
depress_time=10) at ../kern/syscall_subr.c:321
#3  0x80127a39 in swtch_pri (pri=0) at ../kern/syscall_subr.c:131
#4  0x801083a8 in mach_call_call () at ../i386/i386/locore.S:1101
#5  0x in ?? ()
(gdb) c
Continuing.
^C
Program received signal SIGINT, Interrupt.
db_load_context (pcb=0xe19b83c0) at ../i386/i386/db_interface.c:80
80  set_dr3(pcb->ims.ids.dr[3]);
(gdb) bt
#0  db_load_context (pcb=0xe19b83c0) at ../i386/i386/db_interface.c:80
#1  0x8010881d in switch_ktss (pcb=0xe19b83c0) at ../i386/i386/pcb.c:219
#2  0x80108921 in stack_handoff (old=0xe19eabe0, new=0xe19b7000) at 
../i386/i386/pcb.c:294
#3  0x80126826 in thread_invoke (old_thread=0xe19eabe0, 
continuation=0x801278b0 , new_thread=0xe19b7000) at 
../kern/sched_prim.c:675
#4  0x80126e64 in thread_block (continuation=0x801278b0 
) at ../kern/sched_prim.c:890
#5  0x80127a45 in swtc

UTIME_{NOW,OMIT} needed for util-linux

[Samuel Thibault]

As seen on IRC:

 Hi. Just a short service announcement... the libmount/fsck
patches got merged upstream for the benefit of kFreeBSD. This will
mean that next upstream util-linux release will FTBFS on Hurd. See
https://lists.debian.org/debian-hurd/2014/08/msg00011.html for more details.

And also explained a bit on http://darnassus.sceen.net/~hurd-web/contributing/

So, anybody up for this?

Samuel

Re: [PATCH] Update NEWS file

[Samuel Thibault]

Guillem Jover, le Wed 24 Sep 2014 16:14:52 +0200, a écrit :
> Might I suggest that people tweak their repos so that we get more
> meaningful subject lines on «git format-patch», these three were
> quite confusing at first.

Yes, and that's not the first time this happens :)

Samuel

Re: [PATCH] Update NEWS file

[Samuel Thibault]

Ack.

Justus Winter, le Wed 24 Sep 2014 15:05:06 +0200, a écrit :
> ---
>  NEWS | 22 ++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/NEWS b/NEWS
> index 72a2e2d..b047aed 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -1,3 +1,25 @@
> +2013-XX-XX
> +Version 0.6
> +
> +Numerous cleanups and stylistic fixes of the code base.  Several
> +problems have been identified using static analysis and exercising
> +tools, and have subsequently been fixed.
> +
> +The message dispatching code in the Hurd servers has been improved.
> +
> +The embedded gz and bz2 decompressor code has been removed, libz and
> +libbz2 is used instead.
> +
> +The native fakeroot tool has been greatly improved and is now able to
> +build many packages.  The portinfo and rpctrace tools now offer a
> +better debugging experience.
> +
> +The performance of the integer hashing library has been improved.
> +
> +The procfs translator has been merged.
> +
> +The random translator has been merged.
> +
>  2013-09-27
>  Version 0.5
>  
> -- 
> 2.1.0
> 

-- 
Samuel
"c'est pas nous qui sommes à la rue, c'est la rue qui est à nous"

Re: [PATCH] Update NEWS file

[Samuel Thibault]

Ack.

Justus Winter, le Wed 24 Sep 2014 15:03:24 +0200, a écrit :
> ---
>  NEWS | 16 
>  1 file changed, 16 insertions(+)
> 
> diff --git a/NEWS b/NEWS
> index 55d75cc..9a9f620 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -1,3 +1,19 @@
> +2014-XX-XX
> +Version 1.5
> +
> +Numerous cleanups and stylistic fixes of the code base.  Several
> +problems have been identified using static analysis tools and
> +subsequently been fixed.
> +
> +The kernel debugger can now parse ELF symbol tables, can be invoked
> +over serial lines, gained two new commands and has received usability
> +improvements.
> +
> +The vm pageout policy has been tuned to accommodate modern hardware.
> +
> +The kernel gained partial ACPI support on x86, enough to power down
> +the system.
> +
>  2013-09-27
>  Version 1.4
>  
> -- 
> 2.1.0
> 

-- 
Samuel
 what the fuck is wtf

Re: [PATCH] Update NEWS file

[Samuel Thibault]

Ack.

Justus Winter, le Wed 24 Sep 2014 15:04:25 +0200, a écrit :
> ---
>  NEWS | 10 ++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/NEWS b/NEWS
> index 6c1bd19..9fc6b3d 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -1,3 +1,13 @@
> +2013-XX-XX
> +Version 1.5
> +
> +* Emit `X_server_routine' functions that can be inlined reducing the
> +  message dispatch overhead.
> +
> +* Improve support for variable-sized c strings.
> +
> +* Fix a warning when compiling generated files.
> +
>  2013-09-27
>  Version 1.4
>  
> -- 
> 2.1.0
> 

-- 
Samuel
/* Amuse the user. */
printk(
"  \\|/  \\|/\n"
"  \"@'/ ,. \\`@\"\n"
"  /_| \\__/ |_\\\n"
" \\__U_/\n");
(From linux/arch/sparc/kernel/traps.c:die_if_kernel())

Re: [PATCH] Update NEWS file

[Guillem Jover]

Hi!

Might I suggest that people tweak their repos so that we get more
meaningful subject lines on «git format-patch», these three were
quite confusing at first. Something like the following per repo?

  $ git config format.subjectprefix 'PATCH gnumach'

Thanks,
Guillem

[PATCH] Update NEWS file

[Justus Winter]

---
 NEWS | 16 
 1 file changed, 16 insertions(+)

diff --git a/NEWS b/NEWS
index 55d75cc..9a9f620 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,19 @@
+2014-XX-XX
+Version 1.5
+
+Numerous cleanups and stylistic fixes of the code base.  Several
+problems have been identified using static analysis tools and
+subsequently been fixed.
+
+The kernel debugger can now parse ELF symbol tables, can be invoked
+over serial lines, gained two new commands and has received usability
+improvements.
+
+The vm pageout policy has been tuned to accommodate modern hardware.
+
+The kernel gained partial ACPI support on x86, enough to power down
+the system.
+
 2013-09-27
 Version 1.4
 
-- 
2.1.0

[PATCH] Update NEWS file

[Justus Winter]

---
 NEWS | 22 ++
 1 file changed, 22 insertions(+)

diff --git a/NEWS b/NEWS
index 72a2e2d..b047aed 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,25 @@
+2013-XX-XX
+Version 0.6
+
+Numerous cleanups and stylistic fixes of the code base.  Several
+problems have been identified using static analysis and exercising
+tools, and have subsequently been fixed.
+
+The message dispatching code in the Hurd servers has been improved.
+
+The embedded gz and bz2 decompressor code has been removed, libz and
+libbz2 is used instead.
+
+The native fakeroot tool has been greatly improved and is now able to
+build many packages.  The portinfo and rpctrace tools now offer a
+better debugging experience.
+
+The performance of the integer hashing library has been improved.
+
+The procfs translator has been merged.
+
+The random translator has been merged.
+
 2013-09-27
 Version 0.5
 
-- 
2.1.0

[PATCH] Update NEWS file

[Justus Winter]

---
 NEWS | 10 ++
 1 file changed, 10 insertions(+)

diff --git a/NEWS b/NEWS
index 6c1bd19..9fc6b3d 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,13 @@
+2013-XX-XX
+Version 1.5
+
+* Emit `X_server_routine' functions that can be inlined reducing the
+  message dispatch overhead.
+
+* Improve support for variable-sized c strings.
+
+* Fix a warning when compiling generated files.
+
 2013-09-27
 Version 1.4
 
-- 
2.1.0