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ntp: optimize resizing of hash table with sources

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This commit is contained in:
Miroslav Lichvar 2016-02-02 12:00:58 +01:00
parent 400820d3f3
commit beaf275222
1 changed files with 5 additions and 4 deletions
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9
ntp_sources.c
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@ -57,7 +57,8 @@ typedef struct {
sources from the pool respond first */
} SourceRecord;
/* Hash table of SourceRecord, the size should be a power of two */
/* Hash table of SourceRecord, its size is a power of two and it's never
more than half full */
static ARR_Instance records;
/* Number of sources in the hash table */
@ -233,12 +234,12 @@ find_slot(NTP_Remote_Address *remote_addr, int *slot, int *found)
}
/* ================================================== */
/* Check if hash table of given size is sufficient to contain sources */
static int
check_hashtable_size(unsigned int sources, unsigned int size)
{
return sources * 2 + 1 < size;
return sources * 2 <= size;
}
/* ================================================== */
@ -256,7 +257,7 @@ rehash_records(void)
memcpy(temp_records, ARR_GetElements(records), old_size * sizeof (SourceRecord));
/* The size of the hash table is always a power of two */
for (new_size = 4; !check_hashtable_size(n_sources, new_size); new_size *= 2)
for (new_size = 1; !check_hashtable_size(n_sources, new_size); new_size *= 2)
;
ARR_SetSize(records, new_size);