diff --git a/meetings/2024-08-13-minutes.md b/meetings/2024-08-13-minutes.md new file mode 100644 index 0000000..ca97d48 --- /dev/null +++ b/meetings/2024-08-13-minutes.md @@ -0,0 +1,52 @@ +# Meeting Minutes 2024-08-13 + +- CX TG Requirements Ad-Hoc Meeting: Single or Multiple Contexts + +- Attendees + + Darius Rad (Bluespec) + Jan Gray (Individual) + Guy Lemieux (Individual) + Victor Lu (Individual) + +- Discussion + +Jan proposed meeting rules, objectives (better mutual understanding of +the proposals, but not a decision). + +Guy asked for clarification about the specific topic of the discussion. +Darius stated that the topic is multiple potential requirements related +to the general concept of one or multiple state contexts per hart, +and not a simple binary question. + +Jan presented his position that multiple state contexts per hart is a more +novel, more complex, but more flexible, more performant, affordable, and +preferable approach to achieve the goals of the task group. His position +was presented from the perspective of the user programming model and +suggested other perspectives be clear about which level of abstraction +they are referring to. He described a number of use cases in support +of this position. + +Guy questioned whether objection to multiple state contexts is due to +memory table mechanism in basis specification, for which he is designing +an alternative. + +Guy proposed the following requirements: +* Must efficiently support hardware implementation for single context per hart +* Should efficiently support hardware implementation for multiple contexts per hart +* Must convey a single programming model in either case +* Must support >1 context per thread without context switching + +Darius presented his position that a single state context per hart is more +consistent with existing RISC-V extensions and that existing mechanisms +for context management in the operating system and in user level software +may be utilized to achieve the goals of the task group. He indicated +that the behavior of one state context per hart is more consistent with +the expected programming model at the ISA level in all privilege modes. + +There was discussion regarding whether a single state per hart or multiple +states per hart need to be mutually exclusive requirements. + +There was discussion regarding whether extension state should be +considered hart state, or not, or if both behaviors could be or should +be supported.