J3/15-151r1 To: J3 From: John Reid & Bill Long Subject: Replacement for stalling Date: 2015 February 25 Discussion ---------- In the recent ballot (see N2045), Robert Corbett voted "no" and wrote "I am still concerned about the features described in Clause 5.9 I understand that allowing stalled images to resume execution is a desired feature. I am not convinced that the feature as described in the DTS can be implemented without imposing a severe performance penalty. I understand that the ability to resume stalled images is an optional feature. I think that even an optional feature should be required to be implementable." Malcolm Cohen also voted *no" saying "I agree with Robert Corbett's vote." Van Snyder also voted *no" saying "I am concerned by Robert Corbett's comments." In a straw vote, J3 recommended replacing the concept of stalling by continued execution using a processor-dependent value when a data object is referenced on a failed image. Another paper removes the concept of stalling. This paper addresses continued execution. Edits to N2040: --------------- [11:4-6] Replace R624 and C509 by "R624 <> <> <> [, ] <> <> [, STAT = ] R624a <> TEAM_ID = <> TEAM = C509 (R624) shall not be a coindexed object." {This replaces the edit for these lines in 15-124.} [11:14+] Add "NOTE 5.2a The use of a STAT=specifier in an image selector allows a test to be made for a failed image in a reference where the use of a processor- dependent result could cause error termination or an incorrect execution path. Where there is no such possibility, it may be preferable to rely on the STAT=specifier in the next image control statement.". [13:21] After "image control statement", add ",a reference to a coindexed object,". [13:24] After "image control statement", add " or a reference to a coindexed object". [14:12+] Add paragraph "Defining a coindexed object on a failed image has no effect other than defining the , if one appears, with the value STAT_FAILED_IMAGE. The value of an expression that includes a reference to a coindexed object on a failed image is processor dependent. Execution continues after such reference.". [44:13+] At the end of line 13, replace "." by ";" and add a new entry: "the value of an expression that includes a reference to a coindexed object on a failed image."