Call for Discussion: New Project: Skara -- sample repacked git repo of JDK 12 sources now available

Aleksey Shipilev shade at redhat.com
Mon Aug 13 07:51:22 UTC 2018


On 08/13/2018 07:26 AM, joe darcy wrote:
> PPS A repacked sample git repo, as alluded to earlier in this thread and as discussed in the Skara
> presentation from the OpenJDK Committers’ Workshop, equivalent to a recent snapshot of JDK 12 is
> available for browsing and cloning from:
> 
>     git clone https://github.com/Project-Skara/jdk.git
>     https://github.com/Project-Skara/jdk
> 

Nice! Some performance data from Germany:

$ time git clone https://github.com/Project-Skara/jdk.git
Cloning into 'jdk'...
remote: Counting objects: 881253, done.
remote: Compressing objects: 100% (160363/160363), done.
remote: Total 881253 (delta 665729), reused 881253 (delta 665729), pack-reused 0
Receiving objects: 100% (881253/881253), 258.61 MiB | 5.32 MiB/s, done.
Resolving deltas: 100% (665729/665729), done.
Checking out files: 100% (66258/66258), done.

real	1m25.508s
user	1m8.522s
sys	0m6.595s

For the comparison, pulling the .hg workspace snapshot:

$ time (curl https://builds.shipilev.net/workspaces/jdk-jdk.tar.xz | tar xJf -; cd jdk-jdk; hg pull;
hg up;)
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  752M  100  752M    0     0  5673k      0  0:02:15  0:02:15 --:--:-- 5737k
pulling from http://hg.openjdk.java.net/jdk/jdk
searching for changes
adding changesets
adding manifests
adding file changes
added 116 changesets with 1065 changes to 858 files
new changesets cf34c71ca27c:802f7e5e7e6b
(run 'hg update' to get a working copy)
66288 files updated, 0 files merged, 0 files removed, 0 files unresolved


real	2m31.941s
user	1m35.735s
sys	0m22.859s

It looks that the limiting factor here is the actual network bandwidth. So, the performance is in
the same ballpark, and if .hg would be smaller (my experiments saw 1.3x decreases with enabling some
Mercurial options), we can get this down to 2 minutes.

-Aleksey



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