On Thu, May 29, 2014 at 11:36 PM, Junio C Hamano <gits...@pobox.com> wrote: > Duy Nguyen <pclo...@gmail.com> writes: > >> On Thu, May 29, 2014 at 6:49 AM, David Turner <dtur...@twopensource.com> >> wrote: >>>> I assume that most of the time spent in check_refname_component() is >>>> while reading the packed-refs file, right? >>> >>> Yes. >> >> I wonder if we can get away without SSE code by saving stat info of >> the packed-refs version that we have verified. When we read pack-refs, >> if stat info matches, skip check_refname_component(). Assuming that >> pack-refs does not change often, of course. > > Can you elaborate a bit more?
The first time we read packed_refs, check_refname_format() is called in read_packed_refs()->create_ref_entry() as usual. If we find no problem, we store packed_refs stat() info in maybe packed_refs.stat. Next time we read packed_refs, if packed_refs.stat is there and indicates that packed_refs has not changed, we can make create_ref_entry() ignore check_refname_format() completely. That's even cheaper than SSE-enhanced check_refname_component() and easier to do. If packed_refs is updated, we do the whole check_refname_format dance again. -- Duy -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
