On 30 May 2012 20:52, <rhuij...@apache.org> wrote: > Author: rhuijben > Date: Wed May 30 16:52:36 2012 > New Revision: 1344347 > > URL: http://svn.apache.org/viewvc?rev=1344347&view=rev > Log: > Remove about 15% of the cpu overhead of svnserve and httpd while running the > test suite by introducing a very simple parser buffer in the config file > parser > code. > > The nice clean stream translation code had an 7 times overhead on this very > performance critical code path, while clients of svnserve and httpd were > waiting. (Before this patch the this code path used 22% of the cpu time, > now just 3%) > > * subversion/libsvn_subr/config_file.c > (parse_context_t): Add buffer and position variables. Use EOF as no ungetc > var. > (parser_getc): Skip '\r' characters as we only need the '\n' character for > our > config files. Use EOF as no ungetc var. > (parse_option, > parse_section_name): Rename pool argument to scratch_pool. > (svn_config__parse_file): Create scratch pool and store the file and parse > ctx in it. Update initialization and destroy scratch_pool after > successfull > parsing. > > Modified: > subversion/trunk/subversion/libsvn_subr/config_file.c > > Modified: subversion/trunk/subversion/libsvn_subr/config_file.c > URL: > http://svn.apache.org/viewvc/subversion/trunk/subversion/libsvn_subr/config_file.c?rev=1344347&r1=1344346&r2=1344347&view=diff > ============================================================================== > --- subversion/trunk/subversion/libsvn_subr/config_file.c (original) > +++ subversion/trunk/subversion/libsvn_subr/config_file.c Wed May 30 16:52:36 > 2012 > @@ -60,15 +60,19 @@ typedef struct parse_context_t > /* The current line in the file */ > int line; > > - /* Cached ungotten character - streams don't support ungetc() > - [emulate it] */ > + /* Emulate an ungetc */ > int ungotten_char; > - svn_boolean_t have_ungotten_char; > > - /* Temporary strings, allocated from the temp pool */ > + /* Temporary strings */ > svn_stringbuf_t *section; > svn_stringbuf_t *option; > svn_stringbuf_t *value; > + > + /* Parser buffer for getc() to avoid call overhead into several libraries > + for every character */ > + char parser_buffer[SVN_STREAM_CHUNK_SIZE]; /* Larger than most config > files */ Hi Bert,
Did you have specific reasons for using deprecated SVN_STREAM_CHUNK_SIZE (100 kb) instead of SVN__STREAM_CHUNK_SIZE (16kb) constant for read buffer? I'm asking because it seems this significantly increase memory footprint for high loaded servers due APR allocator behavior and fragmentation. I would like change this buffer to 16kb instead of 100kb, if you don't have strong objections. -- Ivan Zhakov CTO | VisualSVN | http://www.visualsvn.com
