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CSP: Introduce a one element sliding buffer when DB changes are saved

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This fixes a deadlock issue from the previous model.
This commit is contained in:
Nicholas Kariniemi 2015-08-24 18:38:38 +03:00
parent b3b8011719
commit 619f21e4d8
1 changed files with 12 additions and 6 deletions
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18
csp/sync.csp
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@ -2,7 +2,7 @@ N = 2
S = 3
CLIENTS = {0..N-1}
STATES = {0..S-1}
channel input, render, up, down, save, saved:CLIENTS.STATES
channel input, render, up, down, save, saved, bufsave, bufsaved:CLIENTS.STATES
apply(state, patch) = (state + patch) % S
diff(state1, state2) = (state2 - state1) % S
@ -30,19 +30,25 @@ CLIENT'(i, state, shadow) = down!i?patch
SERVER(i, shadow) =
up!i?patch
-> save!i!patch
-> saved!i?new_state
-> bufsaved!i?new_state
-> down!i!diff(apply(shadow, patch), new_state)
-> SERVER(i, apply(shadow, patch))
[] saved?j?new_state
[] bufsaved?j?new_state
-> if (new_state == shadow)
then SERVER(i, shadow)
else down!i!diff(shadow, new_state) -> SERVER(i, new_state)
DB(state) = save?i?patch
-> saved!i!apply(state, patch)
BUF(i) = saved?j?new_state -> BUF'(i, j, new_state)
BUF'(i, j, new_state) = saved?j'?new_state' -> BUF'(i, j', new_state')
[] bufsaved!j!new_state -> BUF(i)
DB(state) = save?i?patch
-> saved!i!apply(state, patch)
-> DB(apply(state, patch))
CONN(i, init) = CLIENT(i, init, init) [|{| up.i, down.i |}|] SERVER(i, init)
DBB = DB(0)
CONN(i, init) = (CLIENT(i, init, init) [|{| up.i, down.i |}|] SERVER(i, init)) [|{| bufsaved |}|] BUF(i)
SYSTEM = (CONN(0,0) [|{| save.0, saved |}|] DB(0)) [|{| save.1, saved |}|] CONN(1,0)