RepoMirrors/ceph
1
0
Fork 0
mirror of https://github.com/ceph/ceph synced 2025-02-22 02:27:29 +00:00
Code Issues Packages Projects Releases Wiki Activity

common/FastCDC: better behavior if TARGET_WINDOW_BITS==0

Browse Source 
Skip the middle scan call entirely in that case.

Signed-off-by: Sage Weil <sage@newdream.net>
This commit is contained in:
Sage Weil 2020-05-21 10:36:28 -05:00
parent afb5b81adb
commit 264cce3139
1 changed files with 15 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
src/common/FastCDC.cc
View File

@ -155,18 +155,21 @@ void FastCDC::calc_chunks(
ceph_assert(pos < len);
// find an end marker
if (_scan(&p, &pp, &pe, pos, // for the first "small" region
std::min(len,
cstart + (1 << (target_bits - TARGET_WINDOW_BITS))),
fp, small_mask, table) &&
_scan(&p, &pp, &pe, pos, // for the middle range (close to our target)
std::min(len,
cstart + (1 << (target_bits + TARGET_WINDOW_BITS))),
fp, target_mask, table) &&
_scan(&p, &pp, &pe, pos, // we're past target, use large_mask!
std::min(len,
cstart + (1 << max_bits)),
fp, large_mask, table)) ;
if (
// for the first "small" region
_scan(&p, &pp, &pe, pos,
std::min(len, cstart + (1 << (target_bits - TARGET_WINDOW_BITS))),
fp, small_mask, table) &&
// for the middle range (close to our target)
(TARGET_WINDOW_BITS == 0 ||
_scan(&p, &pp, &pe, pos,
std::min(len, cstart + (1 << (target_bits + TARGET_WINDOW_BITS))),
fp, target_mask, table)) &&
// we're past target, use large_mask!
_scan(&p, &pp, &pe, pos,
std::min(len,
cstart + (1 << max_bits)),
fp, large_mask, table)) ;
chunks->push_back(std::pair<uint64_t,uint64_t>(cstart, pos - cstart));
}