From: Johannes Schindelin Date: Wed, 14 Sep 2005 08:38:58 GMT Subject: Re: dumb transports not being welcomed.. Message-ID: In-Reply-To: Hi, On Tue, 13 Sep 2005, Linus Torvalds wrote: > > On Wed, 14 Sep 2005, Johannes Schindelin wrote: > > > > IMHO the culprit is git-rev-list, which takes ages and ages for big > > repositories (beware: this could be my Darwin client which might be > > incapable to stop the rev enumeration in time; but if that can be done > > unintentionally, this can be intentionally, too!). > > Packed too? Yes. Almost all of it. > git-rev-list will take a long time if the tree is unpacked and not in the > cache. It's all disk seeks. That's _especially_ true of a full clone > (which will walk the whole way down). That could be the case, but my test case is a CVS project I track on one side, and I fetch on the other side. Therefore, your diagram from your other mail does not really apply. My history looks more or less like this: a b c d origin | | | | \ \ \ \ | ---------| So, the origin is a linear CVS project. With many, many, many commits. At one stage I broke off new git branches. I kept tracking the CVS project, though. What I see when fetching all heads (thanks to Junio, this is one call to git-fetch now), where all but origin are up to date, is that it takes a very long time. Swapping kicks in, and top tells me that 26.6% of the memory is occupied by git-rev-list (The server has 128M, with 1G swap, and I am unfortunately not the only user of this machine). I fail to see why it should need those amounts of memory. (I tested this over the ssh protocol, which should essentially do the same as git-daemon, right?) After all, the merge point between the branches should be marked uninteresting after one single step from each of my private branches. > But I have tons of memory in my machines, and I haven't looked at how > badly it does if you don't have that. I know that master.kernel.org is > certainly not having any trouble at all with me pulling from lots of > trees.. Maybe git-rev-list uses up lots of your memory. That certainly is the case. As for master.kernel.org: Unfortunately, you will not be the only puller. And if your process needs just 5% of the RAM, then 21 pullers will be too many. > That said, I do think that --objects handling is _very_ CPU-hungry. In my experience, before the swapping started, the process did not get more than 20% CPU. Nevertheless, I still think that it would be a good idea to reuse the files created for the dumb transport for the intelligent transport. Especially for a project which is more often fetched than uploaded. I also see other strange things like packing 0 objects, and packing >0 objects after just having fetched from that repository. Hopefully I will have time to look into that (and understand the code to begin with). Ciao, Dscho