bug#23979: [ER] guix gc should tell how much space it recovered

bug#23979: [ER] guix gc should tell how much space it recovered

[Vincent Legoll]

It already shows:
note: currently hard linking saves 485.41 MiB

Recovered disk space would nicely complement that.

I could be mentored to do it myself, but I'm very new to guile & guix
;-)

I'd at least require high level directions as to where I should look (in
the code) to graft that functionality.

-- 
Vincent Legoll

bug#23979: [ER] guix gc should tell how much space it recovered

[Vincent Legoll]

Looks like I helped myself out of step 1:
this is in guix/scripts/gc.scm if I'm not mistaken

-- 
Vincent Legoll

bug#23979: [ER] guix gc should tell how much space it recovered

[Ludovic Courtès]

Vincent Legoll <vincent.legoll@gmail.com> skribis:

> It already shows:
> note: currently hard linking saves 485.41 MiB
>
> Recovered disk space would nicely complement that.

Indeed.

> Looks like I helped myself out of step 1:
> this is in guix/scripts/gc.scm if I'm not mistaken

Yep, you’re on the right track!

This code calls the ‘collect-garbage’ procedure, defined in (guix
store).  You’ll see that this procedure returns two values, which are
currently ignored: the name of the items that were removed from the
store, and the number of bytes freed.

Your mission, if you accept it, is to change gc.scm to retrieve this
second value and to display it in a human-friendly way.  :-)

HTH!

Ludo’.

bug#23979: [ER] guix gc should tell how much space it recovered

[Andreas Enge]

On Fri, Jul 15, 2016 at 04:33:46PM +0200, Ludovic Courtès wrote:
> This code calls the ‘collect-garbage’ procedure, defined in (guix
> store).  You’ll see that this procedure returns two values, which are
> currently ignored: the name of the items that were removed from the
> store, and the number of bytes freed.

Brutto or netto? Otherwise said, does it take into account the hardlinks
used for deduplication, or does it pretend that every deleted file saves
as much memory as its size indicates?

Andreas

bug#23979: [ER] guix gc should tell how much space it recovered

[Ludovic Courtès]

Andreas Enge <andreas@enge.fr> skribis:

> On Fri, Jul 15, 2016 at 04:33:46PM +0200, Ludovic Courtès wrote:
>> This code calls the ‘collect-garbage’ procedure, defined in (guix
>> store).  You’ll see that this procedure returns two values, which are
>> currently ignored: the name of the items that were removed from the
>> store, and the number of bytes freed.
>
> Brutto or netto? Otherwise said, does it take into account the hardlinks
> used for deduplication, or does it pretend that every deleted file saves
> as much memory as its size indicates?

The latter, I think.  The actual computation is done by the daemon, in
libstore/gc.cc.

Ludo’.

bug#23979: [ER] guix gc should tell how much space it recovered

[Vincent Legoll]

Here is an attempt:

https://lists.gnu.org/archive/html/guix-devel/2016-07/msg00574.html

I tried to use call-with-values, but couldn't make it to work so
reverted back to let-values...

To test, I added (guix-gc "-C") at the end of the script and ran "guix
pull && guile gc.scm", looked OK...

-- 
Vincent Legoll

bug#23979: Fix merged

[Vincent Legoll]

in git commit :
1187a27112be10f2ff74144f50c88714ccf30301

following submission in :
https://lists.gnu.org/archive/html/guix-devel/2016-07/msg00574.html

Thanks for the help

-- 
Vincent Legoll