GNU bug report logs - #41702
`guix environment` performance issues

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From: Ludovic Courtès <ludo <at> gnu.org>
To: Lars-Dominik Braun <ldb <at> leibniz-psychology.org>
Cc: 41702 <at> debbugs.gnu.org
Subject: bug#41702: `guix environment` performance issues
Date: Wed, 01 Jul 2020 12:49:51 +0200

Hi,

Ludovic Courtès <ludo <at> gnu.org> skribis:

> +    (when open-connection
> +      (let* ((sock (open-connection host port)))
> +        ;; Since 'session-set!' doesn't increase the revealed count of SOCK
> +        ;; (as of Guile-SSH 0.12.0), do it ourselves.
> +        (set-port-revealed! sock 1)
> +        (session-set! session 'fd sock)))

The problem with this approach is that ‘open-connection’ is past the raw
host name; aliases, proxy commands, etc. from ~/.ssh/config are ignored.

So it cannot go in as is.  :-/

What we need is Guile-SSH bindings for ‘ssh_get_fd’, which would allow
us to get at the actual file descriptor after the connection has been
opened, and to set TCP_NODELAY there:

  http://api.libssh.org/stable/group__libssh__session.html#gafe509fcea47714b5cd277d1e35e83276

It’s not 100% clear though if it returns that “right” FD when there’s a
proxy command.

Ludo’.

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