Bug 690581

Summary: extensive output to stderr from pstoraster degrades printing performance
Product: Ghostscript Reporter: Osamu Mihara <osamu.mihara>
Component: CUPS driverAssignee: Till Kamppeter <till.kamppeter>
Status: RESOLVED FIXED    
Severity: normal CC: till.kamppeter
Priority: P4    
Version: 0.00   
Hardware: PC   
OS: Linux   
Customer: Word Size: ---

Description Osamu Mihara 2009-06-29 01:54:00 UTC 
In CUPS system, pstoraster filter outputs massive debug messages to stderror
while printing.  It degrades printing performance, even if debug logging is
turned of by CUPS configuration.

In our measurement, it affects mainly on FPOT (first print out time - time to
hit "start" key to first page is printed).  With a low-end laser printer, FPOT
is 42sec with an OpenOffice.org word document (5 pages).  With modified
pstoraster, which dumps output to stderr to /dev/null, FPOT is improved to 32
sec - about 30% faster.

Please consider to remove "-dDEBUG" option in the pstoraster script, or some
other countermeasures.
Comment 1 Ray Johnston 2009-06-29 09:35:02 UTC 
Seems very reasonable to me.

We probably need to remove 'mike@easysw.com' from the automatic assignment
here and change it over to Ralph.

Assigning to Ralph.
Comment 2 Hin-Tak Leung 2010-07-05 04:55:03 UTC 
Till: can you comment on what cups uses the stderror output of pstoraster for, and what can be removed?
Comment 3 Till Kamppeter 2010-07-05 12:42:21 UTC 
The stderr output serves only for conveying status and error information to the log files of CUPS (error_log and page_log). For me logging also lokks exaggerated and it is really possible that the CUPS raster output device uses more CPU time on logging than on its actual work.

The "-dDEBUG" in pstoraster and pdftoraster are really not necessary.
Comment 4 Hin-Tak Leung 2010-07-05 22:14:08 UTC 
(In reply to comment #3)
> The stderr output serves only for conveying status and error information to the
> log files of CUPS (error_log and page_log). For me logging also lokks
> exaggerated and it is really possible that the CUPS raster output device uses
> more CPU time on logging than on its actual work.
> 
> The "-dDEBUG" in pstoraster and pdftoraster are really not necessary.

My question was probably, what is the minimum debug stderr output needed, for CUPS's status/error info tracking to still work correctly?
Comment 5 Hin-Tak Leung 2010-08-02 00:32:28 UTC 
Re-assigning bugs which still have work to do.
Comment 6 Till Kamppeter 2010-08-12 18:11:19 UTC 
Fixed in SVN rev. 11630.