From: Jeff Hostetler <jeffhost@xxxxxxxxxxxxx>
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), this change 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.
Jeff Hostetler (6):
name-hash: specify initial size for istate.dir_hash table
hashmap: allow memihash computation to be continued
hashmap: Add disallow_rehash setting
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
Makefile | 1 +
cache.h | 1 +
hashmap.c | 29 ++-
hashmap.h | 25 ++
name-hash.c | 490 +++++++++++++++++++++++++++++++++++-
t/helper/test-lazy-init-name-hash.c | 264 +++++++++++++++++++
t/perf/p0004-lazy-init-name-hash.sh | 19 ++
7 files changed, 820 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
--
2.7.4
