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* [Bug libfortran/50673] New: very slow I/O with trailing spaces
@ 2011-10-09 11:04 Joost.VandeVondele at pci dot uzh.ch
2011-10-09 12:05 ` [Bug libfortran/50673] " Joost.VandeVondele at pci dot uzh.ch
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: Joost.VandeVondele at pci dot uzh.ch @ 2011-10-09 11:04 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50673
Bug #: 50673
Summary: very slow I/O with trailing spaces
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libfortran
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: Joost.VandeVondele@pci.uzh.ch
The following testcase (derived from CP2K, which required 20min to read a 600Mb
file) is about 100x times slower with gfortran than with ifort (12.0.4)
CHARACTER(LEN=40480) :: line="O 0.12456789 0.123456789 0.123456789"
CHARACTER(LEN=2) :: AA
REAL*8 :: vec(3)
DO i=1,10000
read(line,*) AA,vec
ENDDO
END
The issue seems related to how efficient the trailing spaces are handled in
both compilers. 4.7 is a bit (20%) slower than 4.3, but nothing fundamental.
Profiling the code shows that most time is spent in next_char, mem_read,
memcpy, eat_spaces.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug libfortran/50673] very slow I/O with trailing spaces
2011-10-09 11:04 [Bug libfortran/50673] New: very slow I/O with trailing spaces Joost.VandeVondele at pci dot uzh.ch
@ 2011-10-09 12:05 ` Joost.VandeVondele at pci dot uzh.ch
2012-04-15 11:54 ` tkoenig at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Joost.VandeVondele at pci dot uzh.ch @ 2011-10-09 12:05 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50673
--- Comment #1 from Joost VandeVondele <Joost.VandeVondele at pci dot uzh.ch> 2011-10-09 12:04:55 UTC ---
Actually, since eating the trailing spaces is the issue (seems to be
implemented very generally in libfortran), the following is a practical
workaround in this case:
read(line(1:LEN_TRIM(line)),*) AA,vec
maybe something along these lines could be done in the runtime ?
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug libfortran/50673] very slow I/O with trailing spaces
2011-10-09 11:04 [Bug libfortran/50673] New: very slow I/O with trailing spaces Joost.VandeVondele at pci dot uzh.ch
2011-10-09 12:05 ` [Bug libfortran/50673] " Joost.VandeVondele at pci dot uzh.ch
@ 2012-04-15 11:54 ` tkoenig at gcc dot gnu.org
2012-04-15 11:57 ` tkoenig at gcc dot gnu.org
2012-04-17 19:34 ` burnus at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: tkoenig at gcc dot gnu.org @ 2012-04-15 11:54 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50673
Thomas Koenig <tkoenig at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |FIXED
AssignedTo|unassigned at gcc dot |tkoenig at gcc dot gnu.org
|gnu.org |
--- Comment #3 from Thomas Koenig <tkoenig at gcc dot gnu.org> 2012-04-15 11:53:44 UTC ---
Fixed on trunk, closing.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug libfortran/50673] very slow I/O with trailing spaces
2011-10-09 11:04 [Bug libfortran/50673] New: very slow I/O with trailing spaces Joost.VandeVondele at pci dot uzh.ch
2011-10-09 12:05 ` [Bug libfortran/50673] " Joost.VandeVondele at pci dot uzh.ch
2012-04-15 11:54 ` tkoenig at gcc dot gnu.org
@ 2012-04-15 11:57 ` tkoenig at gcc dot gnu.org
2012-04-17 19:34 ` burnus at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: tkoenig at gcc dot gnu.org @ 2012-04-15 11:57 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50673
--- Comment #2 from Thomas Koenig <tkoenig at gcc dot gnu.org> 2012-04-15 11:52:49 UTC ---
Author: tkoenig
Date: Sun Apr 15 11:52:44 2012
New Revision: 186466
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=186466
Log:
2012-04-15 Thomas Koenig <tkoenig@gcc.gnu.org>
PR libfortran/38199
PR libfortran/50673
* intrinsics/string_intriniscs_inc.c (string_len_trim):
Remove prototypes for string_len_trim and move to...
* libgfortran.h (string_len_trim): ... here and
(string_len_trim_char4): ...here.
* io/unit.c: For non-array internal arrays where we do reading,
adjust the record length to the last non-blank character.
* io/unix.c: Fix typo.
Modified:
trunk/libgfortran/ChangeLog
trunk/libgfortran/intrinsics/string_intrinsics_inc.c
trunk/libgfortran/io/unit.c
trunk/libgfortran/io/unix.c
trunk/libgfortran/libgfortran.h
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug libfortran/50673] very slow I/O with trailing spaces
2011-10-09 11:04 [Bug libfortran/50673] New: very slow I/O with trailing spaces Joost.VandeVondele at pci dot uzh.ch
` (2 preceding siblings ...)
2012-04-15 11:57 ` tkoenig at gcc dot gnu.org
@ 2012-04-17 19:34 ` burnus at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: burnus at gcc dot gnu.org @ 2012-04-17 19:34 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50673
--- Comment #4 from Tobias Burnus <burnus at gcc dot gnu.org> 2012-04-17 19:30:38 UTC ---
Author: burnus
Date: Tue Apr 17 19:30:29 2012
New Revision: 186548
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=186548
Log:
2012-04-17 Tobias Burnus <burnus@net-b.de>
PR libfortran/38199
PR libfortran/50673
* io/unit.c (get_internal_unit): Properly check for the presence
of the format string.
Modified:
trunk/libgfortran/ChangeLog
trunk/libgfortran/io/unit.c
^ permalink raw reply [flat|nested] 5+ messages in thread
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2011-10-09 11:04 [Bug libfortran/50673] New: very slow I/O with trailing spaces Joost.VandeVondele at pci dot uzh.ch
2011-10-09 12:05 ` [Bug libfortran/50673] " Joost.VandeVondele at pci dot uzh.ch
2012-04-15 11:54 ` tkoenig at gcc dot gnu.org
2012-04-15 11:57 ` tkoenig at gcc dot gnu.org
2012-04-17 19:34 ` burnus at gcc dot gnu.org
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