XML Load

ODF Documents are a zipped archive of XML files along with some assorted information and pictures. Reading and parsing the XML constitutes a chunk of the time spent in opening documents. Below is an analysis of XML processing.

We use a suite of 60 Performance Related Test Documents. The content.xml for each has been extracted for XML-only tests.

Niklas and Florian have prototyped a test component, which tokenizes XML tags, and passes tokens around. This saves string allocation times and provides speedup.(FastXML)

Comparisons

• Compare OpenOffice TestXML and TestFastXML for doc sample
• Compare different XML parsers & APIs in terms of processing content.xml
• Compare time spent in XML parsing, building document model, and rendering

Methodology

• Time is measured in the same way for each test - This is based on Time::GetSystemTicks
• File handling and parsing is done as similar as possible - within allowances of API differences.
• Only C and C++ parsers are considered - Java based parsers/wrappers are excluded.

Results

• FastXML provides good speedup, across the test suite.
• Expat is the fastest parser.

Ongoing Work

• Performance counter to measure proportion of time spent in:
  1. Container file uncompress & open
  2. XML Parser setup
  3. Actual Parsing
  4. String Allocation
  5. Building Doc Model
  6. Rendering

The code has been partially instrumented - runs not done yet.