Re: [Bug-apl] segfault when using 'CORE_COUNT_WANTED' configure flag

[Blake McBride]

Greetings,

I think getting the parallel processing working is important.  It may be that for various reasons the speedup in general cases is minimal and not worth the effort.  However, I'd imagine that there are particular use-cases utilizing large arrays where the speedup would be substantial.  That is when those types of enhancements would make APL a real benefit.

Thanks.

Blake

On Wed, Oct 16, 2019 at 5:27 AM Dr. Jürgen Sauermann <mail@jürgen-sauermann.de> wrote:

Hi Rowan,

fixed in SVN 1191.

You should not be too enthusiastic, though, because the speed-ups that
can be achieved are somewhat disappointing. And due to that, I
haven't put too much effort into fixing faults (sometimes apl hangs
on a semaphore when parallel execution is enabled).

Best Regards,
Jürgen Sauermann

On 10/16/19 5:15 AM, Rowan Cannaday wrote:

Hello,

intrigued by the ability to parallelize APL, thought I'd try to test it:

`apl --cfg` followed by a line of '=' signs followed by `apl -q`:


configurable options:
---------------------
    ASSERT_LEVEL_WANTED=2
    SECURITY_LEVEL_WANTED=0 (default)
    APSERVER_PATH=/tmp/GNU-APL/APserver (default)
    APSERVER_PORT=16366 (default)
    APSERVER_TRANSPORT=0 (default)
    CORE_COUNT_WANTED=2
    DYNAMIC_LOG_WANTED=yes
    MAX_RANK_WANTED=8 (default)
    RATIONAL_NUMBERS_WANTED=yes
    SHORT_VALUE_LENGTH_WANTED=12, therefore:
        sizeof(Value)       : 456 bytes
        sizeof(Cell)        :  24 bytes
        sizeof(Value header): 168 bytes

    VALUE_CHECK_WANTED=yes
    VALUE_HISTORY_WANTED=yes
    VF_TRACING_WANTED=no (default)
    VISIBLE_MARKERS_WANTED=yes

how ./configure was (probably) called:
--------------------------------------
    ./configure  'CORE_COUNT_WANTED=2' 'DEVELOP_WANTED=yes' 'VALUE_HISTORY_WANTED=yes' 'VISIBLE_MARKERS_WANTED=yes' '--enable-maintainer-mode'

BUILDTAG:
---------
    Project:        GNU APL
    Version / SVN:  1.8 / 1190M
    Build Date:     2019-10-16 02:45:24 UTC
    Build OS:       Linux 5.2.0-3-amd64 x86_64
    config.status:  'CORE_COUNT_WANTED=2' 'DEVELOP_WANTED=yes' 'VALUE_HISTORY_WANTED=yes' 'VISIBLE_MARKERS_WANTED=yes' '--enable-maintainer-mode'
    Archive SVN:    1161

================================================================================

$ apl -q


====================================================
SEGMENTATION FAULT
thread: 0x7f6078042e00
thread_contexts_count: 2
busy_worker_count:     0
active_core_count:     1
thread # 0:               0 RUN  job:   0 no-name
thread #-1:               0 RUN  job:   0 no-name


----------------------------------------
-- Stack trace at main.cc:88
----------------------------------------
0x7F6078FD1BBB __libc_start_main
0x5631406C386D  main
0x5631406CAD8D   init_apl(int, char const**)
0x5631407E881B    Parallel::init(bool)
0x563140832E2D     Thread_context::init_parallel(CoreCount, bool)
0x7F60794E5B18      sem_init
0x7F60794E8510
0x5631406CA95A
========================================
====================================================