On 3 April 2014 22:15, Julian Foad <julianf...@btopenworld.com> wrote: >>> 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. > [...] >>> * subversion/libsvn_subr/config_file.c >>> (parse_context_t): Add buffer and position variables. Use EOF as no >>> ungetc var. > [...] >>> Modified: subversion/trunk/subversion/libsvn_subr/config_file.c >>> ============================================================================== >>> + >>> + /* Parser buffer for getc() to avoid call overhead into several >>> libraries >>> + for every character */ >>> + char parser_buffer[SVN_STREAM_CHUNK_SIZE]; > [...] > > This commit implements buffering of a generic stream, directly in the config > file parser. Would it > not be better to implement buffering of a generic stream as a generic module? > This commit improved performance over buffer APR file, so switching to back to buffered stream will degrade performance again. Config parser also use parser_buffer knowledge to use extremle optimized memchr() to find end of line to skip comment lines. Config parsers used very often, that's because it should be optimized.
-- Ivan Zhakov
