Optimize expand_name_field() to speed up V4 index parsing. - strbuf_remove() in expand_name_field() is not exactly a good fit for stripping a part at the end, _setlen() would do the same job and is much cheaper. - the open-coded loop to find the end of the string in expand_name_field() can't beat an optimized strlen() I used p0002-read-cache.sh to generate some performance data: p0002-read-cache.sh w/100,000 files Baseline expand_name_field() --------------------------------------- 22.34(0.01+0.12) 21.14(0.03+0.01) -5.4% p0002-read-cache.sh w/1,000,000 files Baseline expand_name_field() ----------------------------------------- 306.44(0.04+0.07) 295.42(0.01+0.07) -3.6% Suggested by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx> Signed-off-by: Ben Peart <Ben.Peart@xxxxxxxxxxxxx> --- read-cache.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/read-cache.c b/read-cache.c index 7b1354d759..382cc16bdc 100644 --- a/read-cache.c +++ b/read-cache.c @@ -1754,9 +1754,8 @@ static unsigned long expand_name_field(struct strbuf *name, const char *cp_) if (name->len < len) die("malformed name field in the index"); - strbuf_remove(name, name->len - len, len); - for (ep = cp; *ep; ep++) - ; /* find the end */ + strbuf_setlen(name, name->len - len); + ep = cp + strlen((const char *)cp); strbuf_add(name, cp, ep - cp); return (const char *)ep + 1 - cp_; } -- 2.18.0.windows.1