From: Jeff Hostetler <jeffhost@xxxxxxxxxxxxx>
Version 2 of this patch series addresses the coding
style issues, compile errors in non-threaded builds,
and updated API documentation.
This patch series is a performance optimization for
lazy_init_name_hash() in name-hash.c on very large
repositories.
This change allows lazy_init_name_hash() to optionally
use multiple threads when building the the_index.dir_hash
and the_index.name_hash hashmaps. The original code path
has been preserved and is used when the repo is small or
the system does not have sufficient CPUs.
A helper command (t/helper/test-lazy-init-name-hash) was
created to demonstrate performance differences and validate
output. For example, use the '-p' option to compare both
code paths on a large repo.
During our testing on the Windows source tree (3.1M
files, 500K folders, 450MB index) with an 8 (logical)
core machine, we reduced the runtime of lazy_init_name_hash()
from 1.4 to 0.27 seconds.
This patch series replaces my earlier
* jh/memihash-opt (2017-02-17) 5 commits
patch series. This series is an improvement over the
original proposal because it completely isolates the changes
in name name-hash.c (rather than having parts in preload-index.c)
and eliminates the need to update/invalidate precomputed hash
values as cache_entries are changed.
Jeff Hostetler (7):
name-hash: specify initial size for istate.dir_hash table
hashmap: allow memihash computation to be continued
hashmap: Add disallow_rehash setting
hashmap: document memihash_cont, hashmap_disallow_rehash api
name-hash: perf improvement for lazy_init_name_hash
name-hash: add test-lazy-init-name-hash
name-hash: add perf test for lazy_init_name_hash
Documentation/technical/api-hashmap.txt | 22 ++
Makefile | 1 +
cache.h | 1 +
hashmap.c | 29 +-
hashmap.h | 25 ++
name-hash.c | 495 +++++++++++++++++++++++++++++++-
t/helper/test-lazy-init-name-hash.c | 264 +++++++++++++++++
t/perf/p0004-lazy-init-name-hash.sh | 19 ++
8 files changed, 847 insertions(+), 9 deletions(-)
create mode 100644 t/helper/test-lazy-init-name-hash.c
create mode 100644 t/perf/p0004-lazy-init-name-hash.sh
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2.7.4