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Remove the wfe() for bounded wait in bakery_lock

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This patch is an optimization in the bakery_lock_get() function
which removes the wfe() when waiting for other contenders to choose
their ticket i.e when their `entering` flag is set. Since the time
taken to execute bakery_get_ticket() by other contenders is bounded,
this wait is a bounded time wait. Hence the removal of wfe() and the
corresponding sev() and dsb() in bakery_get_ticket() may result
in better time performance during lock acquisition.

Change-Id: I141bb21294226b54cb6e89e7cac0175c553afd8d
This commit is contained in:
Soby Mathew 2014-11-18 10:45:04 +00:00 • committed by Dan Handley
parent 1c73ffbd4c
commit d4f4ad90f9
1 changed files with 1 additions and 3 deletions
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4
lib/locks/bakery/bakery_lock.c
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@ -107,8 +107,6 @@ static unsigned int bakery_get_ticket(bakery_lock_t *bakery, unsigned int me)
++my_ticket;
bakery->number[me] = my_ticket;
bakery->entering[me] = 0;
dsb();
sev();
return my_ticket;
}
@ -151,7 +149,7 @@ void bakery_lock_get(bakery_lock_t *bakery)
/* Wait for the contender to get their ticket */
while (bakery->entering[they])
wfe();
;
/*
* If the other party is a contender, they'll have non-zero