Re: Fwd: ostree static-delta

[Colin Walters <walters verbum org>]

 

On Tue, Jul 19, 2016, at 10:09 AM, Colin Walters wrote:

 

1) Doc: "Static deltas also support from NULL, where the client can more efficiently download a commit object from scratch."

 

What is the use case for the --empty command line argument? I feel like the documentation needs some clarification in this area. Even after looking at the code I am still not entirely sure where this is needed.

 

https://github.com/ostreedev/ostree/pull/136#issuecomment-139243553

https://github.com/ostreedev/ostree/pull/402

 

 

2) Doc: "The current delta compiler scans for files with matching basenames in each commit that have a similar size, and attempts a bsdiff between them.

(It would make sense later to have a build system provide a hint for this - for example, files within a same package)."

If I read the code correctly then OSTree won't generate a static delta for libQt5Core.so.5.6.1 -> libQt5Core.so.5.7.0 update. What is a definition of a "basename" here?
With Shell "basename libQt5Core.so.5.6.1" -> "libQt5Core.so.5.6.1"

Yeah, we do need to fix this.  It's https://bugzilla.gnome.org/show_bug.cgi?id=764009

Nevertheless, the testing results on Intel NUC show that update size is reduced by 2/3 when updating

OpenEmbedded image (fido branch -> jethro branch).

 

It's pretty interesting that the wall clock time is so similar though - I'm

guessing I/O performance (perhaps the syncfs()) is the blocker for

your device?