ISAR/libmdbx
3
0
Fork 0
mirror of https://github.com/isar/libmdbx.git synced 2025-02-01 06:48:21 +08:00
Code Issues Packages Projects Releases Wiki Activity

mdbx: refine/speedup dpl_search().

Browse Source 
Change-Id: I712e22ea69f23f61c92be976069f09a85831d086
This commit is contained in:
Leonid Yuriev 2020-01-14 15:15:46 +03:00
parent 7c894f0542
commit 0710b07d7c
1 changed files with 45 additions and 49 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

94
src/elements/core.c
View File

@ -2520,61 +2520,57 @@ static __always_inline MDBX_DPL mdbx_dpl_sort(MDBX_DPL dl) {
SEARCH_IMPL(dp_bsearch, MDBX_DP, pgno_t, DP_SEARCH_CMP)
static unsigned __hot mdbx_dpl_search(MDBX_DPL dl, pgno_t pgno) {
if (dl->sorted < dl->length) {
/* unsorted tail case */
if (mdbx_audit_enabled()) {
for (const MDBX_DP *ptr = dl + dl->sorted; --ptr > dl;) {
assert(ptr[0].pgno < ptr[1].pgno);
assert(ptr[0].pgno >= NUM_METAS);
}
}
/* try linear search until the threshold */
if (dl->length - dl->sorted < SORT_THRESHOLD / 2) {
unsigned i = dl->length;
while (i - dl->sorted > 7) {
if (dl[i].pgno == pgno)
return i;
if (dl[i - 1].pgno == pgno)
return i - 1;
if (dl[i - 2].pgno == pgno)
return i - 2;
if (dl[i - 3].pgno == pgno)
return i - 3;
if (dl[i - 4].pgno == pgno)
return i - 4;
if (dl[i - 5].pgno == pgno)
return i - 5;
if (dl[i - 6].pgno == pgno)
return i - 6;
if (dl[i - 7].pgno == pgno)
return i - 7;
i -= 8;
}
while (i > dl->sorted) {
if (dl[i].pgno == pgno)
return i;
--i;
}
MDBX_DPL it = dp_bsearch(dl + 1, i, pgno);
return (unsigned)(it - dl);
}
/* sort a whole */
dl->sorted = dl->length;
dp_sort(dl + 1, dl + dl->length + 1);
}
if (mdbx_audit_enabled()) {
for (const MDBX_DP *ptr = dl + dl->length; --ptr > dl;) {
for (const MDBX_DP *ptr = dl + dl->sorted; --ptr > dl;) {
assert(ptr[0].pgno < ptr[1].pgno);
assert(ptr[0].pgno >= NUM_METAS);
}
}
MDBX_DPL it = dp_bsearch(dl + 1, dl->length, pgno);
return (unsigned)(it - dl);
switch (dl->length - dl->sorted) {
default:
/* sort a whole */
dl->sorted = dl->length;
dp_sort(dl + 1, dl + dl->length + 1);
__fallthrough; /* fall through */
case 0:
/* whole sorted cases */
if (mdbx_audit_enabled()) {
for (const MDBX_DP *ptr = dl + dl->length; --ptr > dl;) {
assert(ptr[0].pgno < ptr[1].pgno);
assert(ptr[0].pgno >= NUM_METAS);
}
}
return (unsigned)(dp_bsearch(dl + 1, dl->length, pgno) - dl);
#define LINEAR_SEARCH_CASE(N) \
case N: \
if (dl[dl->length - N + 1].pgno == pgno) \
return dl->length - N + 1; \
__fallthrough
/* try linear search until the threshold */
LINEAR_SEARCH_CASE(16); /* fall through */
LINEAR_SEARCH_CASE(15); /* fall through */
LINEAR_SEARCH_CASE(14); /* fall through */
LINEAR_SEARCH_CASE(13); /* fall through */
LINEAR_SEARCH_CASE(12); /* fall through */
LINEAR_SEARCH_CASE(11); /* fall through */
LINEAR_SEARCH_CASE(10); /* fall through */
LINEAR_SEARCH_CASE(9); /* fall through */
LINEAR_SEARCH_CASE(8); /* fall through */
LINEAR_SEARCH_CASE(7); /* fall through */
LINEAR_SEARCH_CASE(6); /* fall through */
LINEAR_SEARCH_CASE(5); /* fall through */
LINEAR_SEARCH_CASE(4); /* fall through */
LINEAR_SEARCH_CASE(3); /* fall through */
LINEAR_SEARCH_CASE(2); /* fall through */
case 1:
if (dl[dl->length].pgno == pgno)
return dl->length;
/* continue bsearch on the sorted part */
return (unsigned)(dp_bsearch(dl + 1, dl->sorted, pgno) - dl);
}
}
static __always_inline MDBX_page *mdbx_dpl_find(MDBX_DPL dl, pgno_t pgno) {