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seqlock: Remove memory barrier if Non-SMP.

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This commit removed unnecessary memory barriers of the seqlock
implementation, since they may block the CPU pipeline and lead to
performance degradation.

Signed-off-by: ouyangxiangzhen <ouyangxiangzhen@xiaomi.com>
This commit is contained in:
ouyangxiangzhen 2025-09-10 09:36:41 +08:00 • committed by Alan C. Assis
parent f1ef43c72e
commit dbc6bedff9
1 changed files with 6 additions and 0 deletions
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6
include/nuttx/seqlock.h
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@ -104,7 +104,10 @@ unsigned int read_seqbegin(FAR const seqcount_t *s)
while ((seq = s->sequence) & 1);
#ifdef CONFIG_SMP
UP_DMB();
#endif
return seq;
}
@ -129,7 +132,10 @@ unsigned int read_seqretry(FAR const seqcount_t *s, unsigned int start)
{
unsigned int seq;
#ifdef CONFIG_SMP
UP_DMB();
#endif
seq = s->sequence;
return seq != start;
}