cdc2c30e99
semaphore locks have much higher overhead than initially presented in the "Semaphores in Plan9" paper. until the reason for it has been found out i will revert the changes.
27 lines
255 B
C
27 lines
255 B
C
#define _LOCK_EXTENSION
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#include "../plan9/sys9.h"
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#include <lock.h>
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int tas(int*);
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void
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lock(Lock *lk)
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{
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while(tas(&lk->val))
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_SLEEP(0);
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}
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int
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canlock(Lock *lk)
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{
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if(tas(&lk->val))
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return 0;
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return 1;
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}
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void
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unlock(Lock *lk)
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{
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lk->val = 0;
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}
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