Re: having trouble modifying guix-daemon

[Robert Vollmert]

> On 1. Jul 2019, at 12:28, Ludovic Courtès <address@hidden> wrote:
> 
> Hello,
> 
> Robert Vollmert <address@hidden> skribis:
> 
>> I’d like to improve the debug output here more generally: At (high enough)
>> debug level, it seems to make sense to log every operation. What I’m unclear
>> on here is whether it’s better to do that client or server side, what do you
>> think? The spots would be
>> 
>> (a) nix/nix-daemon/nix-daemon.cc:performOp (inside each start/stopWork pair)
>> (b) guix/store.scm:operation (next to record-operation)
>> 
>> I have a slight preference for (b) since it avoids the sending data back
>> and forth.
> 
> In my experience I rarely need to log every operation (e.g., every RPC),
> and when I do, I add a well-placed ‘pk’.  :-)

That’s hardly something you’d expect a guix system user to do that’s trying
to understand why guix pull is taking forever though, is it? Compare the
log file of a guix pull run here: http://sprunge.us/jiz2Yl:

00:00:03 acquiring write lock on `/var/guix/temproots/28553'
00:00:03 downgrading to read lock on `/var/guix/temproots/28553'
00:00:03 acquiring write lock on `/var/guix/temproots/28553'
00:00:03 downgrading to read lock on `/var/guix/temproots/28553'
00:00:03 acquiring write lock on `/var/guix/temproots/28553'
00:00:03 downgrading to read lock on `/var/guix/temproots/28553'
00:00:03 acquiring write lock on `/var/guix/temproots/28553'
00:00:03 downgrading to read lock on `/var/guix/temproots/28553'
[…]

Those pages and pages of identical store locking debug messages are worse
than useless. Adding some higher level debug logs in between that show what’s
actually being worked on would help a lot there.

Cheers
Robert