Commits on Oct 23, 2023

1. Switch to simpler fuel APIs …

   In an effort to simplify the many fuel related APIs, simplify the
   interface here to a single counter with get and set methods.
   Additionally the async yield is reduced to an interval of the total fuel
   instead of injecting fuel, so it's easy to still reason about how much
   fuel is left even with yielding turned on.
   
   Internally this works by keeping two counters - one the VM uses to
   increment towards 0 for fuel, the other to track how much is in
   "reserve". Then when we're out of gas, we pull from the reserve to
   refuel and continue. We use the reserve in two cases: one for overflow
   of the fuel (which is an i64 and the API expresses fuel as u64) and the
   other for async yieling, which then the yield interval acts as a cap to
   how much we can refuel with.
   
   This also means that `get_fuel` can return the full range of `u64`
   before this change it could only return up to `i64::MAX`. This is
   important because this PR is removing the functionality to track fuel
   consumption, and this makes the API less error prone for embedders to
   track consumption themselves.
   
   Careful to note that the VM counter that is stored as `i64` can be
   positive if an instruction "costs" multiple units of fuel when the fuel
   ran out.
   
   prtest:full
   
   Signed-off-by: Tyler Rockwood <rockwood@redpanda.com>

   

   rockwotj committed Oct 23, 2023
   Configuration menu

   • View commit details
   • Copy full SHA for eac17cd
   • Browse repository at this point

   Copy the full SHA

   eac17cd View commit details

   Browse the repository at this point in the history