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Marco Realacci 2025-03-18 08:39:12 +01:00
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Concurrent Systems/notes/5 - Software Transactional Memory.md
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@ -120,14 +120,14 @@ So for X, I don't just have to track "who modified X", but also "who modified "Y
We have n processes; process $p_i$ has We have n processes; process $p_i$ has
- for every X, a local copy `lc(XX)` of the implementation of X - for every X, a local copy `lc(XX)` of the implementation of X
- $p\_depend_i[1…m]$ s.t. $p\_depend_i[X]$ is the sequence number of the last val of X (directly or indirectly) known by $p_i$ - $p\_depend_i[1…m]$ s.t. $p\_depend_i[X]$ is the sequence number of the last value of X (directly or indirectly) known by $p_i$
Every transaction T issues by $p_i$ has: Every transaction T issues by $p_i$ has:
- `read_set(T)` and `write_set(T)` - `read_set(T)` and `write_set(T)`
- $t\_depend_{T}[1…m]$ a local copy of $p\_depend_i$ (this is used in the optimistic execution, not to change $p\_depend_{i}$ if T aborts) - $t\_depend_{T}[1…m]$ a local copy of $p\_depend_i$ (this is used in the optimistic execution, not to change $p\_depend_{i}$ if T aborts)
``` ```
begin_T() := begin_T(i) :=
read_set(T), write_set(T) <- ∅ read_set(T), write_set(T) <- ∅
t_depend_T <- p_depend_i t_depend_T <- p_depend_i