From: Julian Phillips Date: Mon, 19 Mar 2007 03:38:03 GMT Subject: Why are ref_lists sorted? Message-ID: Having got a C implementation of fetch far enough to be able to tell me that I'm up-to-date (when using git:// and not using remotes or branches files) I thought I'd compare performance with the fetch--tool based version. I was a bit surprised at what I saw. Hot-cache time went from ~30s to ~3s, which didn't seem too bad. However what did puzzle me was where the C version was spending it's time. Being a work in progress it's a bit chatty in places, but there is an up-front delay of just over 1s (i.e. before my first message, which is the name of the remote to fetch). A bit of investigation showed this to be due to the first attempt to read a ref causing the packed refs to be loaded. In my test repo the packed-refs file has over 9000 entries, but I still thought that it would load faster than that. It turns out that the overhead is from sorting the refs when building the ref_list. If I remove the code for sorting the entries I lose that initial 1s delay, without appearing to break anything in the fetch. However I assume that it's there for a reason ... So my questions are: 1) what have I broken by removing the sort? 2) is it worth trying to optimise the sort? -- Julian --- http://www.ananova.com/news/story/sm_806582.html?menu=news.quirkies SpanKY: my life would have been much improved without that link.