Re: Pack v4 again..

2015-02-16 Thread Shawn Pearce
On Sun, Feb 15, 2015 at 10:45 PM, Jeff King wrote: > On Sun, Feb 15, 2015 at 11:59:02PM -0500, Nicolas Pitre wrote: > >> Yet, I think the biggest problem with pack v4 at the moment is the >> packing algorithm for tree objects. We are piggy-backing on the pack v2 >> object delta compression sortin

Re: Pack v4 again..

2015-02-16 Thread Duy Nguyen
On Mon, Feb 16, 2015 at 1:45 PM, Jeff King wrote: > Somewhat related to this, I was playing this weekend with the idea of > generating fast tree diffs from our on-disk deltas. That is, given a > base tree and a binary delta against it, could I reliably reproduce a > diff (one way or the other) in

Re: Pack v4 again..

2015-02-16 Thread Duy Nguyen
On Mon, Feb 16, 2015 at 11:59 AM, Nicolas Pitre wrote: >> I think pack v4 does not deliver its best promise that walking a tree >> is simply following pointers and jumping from place to place. When we >> want to copy from the middle of another tree, we need to scan from the >> beginning of the tre

Re: Pack v4 again..

2015-02-15 Thread Junio C Hamano
Jeff King writes: > 2. Calculating reachability for packing[1] spends a lot of time in > lookup_object, as we have to go through each tree saying "have we > seen object 1234abcd yet?". If we could instead just view the > differences, we would not have to make those hash lookups f

Re: Pack v4 again..

2015-02-15 Thread Jeff King
On Sun, Feb 15, 2015 at 11:59:02PM -0500, Nicolas Pitre wrote: > Yet, I think the biggest problem with pack v4 at the moment is the > packing algorithm for tree objects. We are piggy-backing on the pack v2 > object delta compression sorting and that produces suboptimal results > due to deep re

Re: Pack v4 again..

2015-02-15 Thread Nicolas Pitre
On Fri, 13 Feb 2015, Duy Nguyen wrote: > After taking 1.5 years "vacation" from pack v4, I plan to do something > about it again. Will post more when I have some patches to discuss. > Only one question for now (forgive me if I asked already, it's been > quite some time) Yeah. I had to re-study m

Pack v4 again..

2015-02-13 Thread Duy Nguyen
After taking 1.5 years "vacation" from pack v4, I plan to do something about it again. Will post more when I have some patches to discuss. Only one question for now (forgive me if I asked already, it's been quite some time) I think pack v4 does not deliver its best promise that walking a tree is s