A hastily convened global energy summit meeting led by Saudi Arabia ended largely in disagreement on Sunday, with only a modest pledge of increased production by the Saudis and no resolution on what other practical steps should be taken to ease the crisis over soaring oil prices. The Saudis, who considered the meeting a success because of the high attendance, announced a production increase of 200,000 barrels a day and an expansion of their output capacity if needed in coming years.