All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jeff King <peff@peff.net>
To: git@vger.kernel.org
Subject: Re: [RFH] gpg --import entropy while running tests
Date: Wed, 28 Dec 2016 03:02:30 -0500	[thread overview]
Message-ID: <20161228080230.wygcmdmwvifcthvl@sigill.intra.peff.net> (raw)
In-Reply-To: <20161228072303.4wbhkwf37fvgpi7h@sigill.intra.peff.net>

On Wed, Dec 28, 2016 at 02:23:03AM -0500, Jeff King wrote:

> That's a lot of time not using any CPU. What's going on? Running with
> "sh -x" shows that we spend most of the time in this line from
> lib-gpg.sh:
> 
>   gpg --homedir "${GNUPGHOME}" 2>/dev/null --import \
> 	  "$TEST_DIRECTORY"/lib-gpg/keyring.gpg
> 
> And running gpg with "--debug-level guru" shows that we are blocking
> while waiting for entropy. Has anybody else seen this? I feel like I
> noticed it starting a few weeks ago, and indeed dropping back to gpg
> 2.0.26 (from 2.1.17) makes the problem go away.
> 
> Is it a bug in gpg (oddly, the kernel reports lots of entropy available,
> and generating the signatures themselves is quite fast)? Or is the new
> version doing something special in the import process that we need to
> work around or disable?

Answering my own question (somewhat): this is bisectable in the gnupg
repository, and it turns out to be caused by their 4473db1ef (agent:
Kludge to mitigate blocking calls in Libgcrypt., 2016-11-11), which
introduces a 100ms sleep (yuck) that is presumably triggering way more
than it needs to. More details at:

  https://git.gnupg.org/cgi-bin/gitweb.cgi?p=gnupg.git;a=commit;h=4473db1ef24031ff4e26c9a9de95dbe898ed2b97

So this does seem like a gpg bug.

-Peff

  reply	other threads:[~2016-12-28  8:02 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-28  7:23 [RFH] gpg --import entropy while running tests Jeff King
2016-12-28  8:02 ` Jeff King [this message]
2016-12-28  8:39   ` Jeff King
2016-12-28 16:05     ` Theodore Ts'o

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20161228080230.wygcmdmwvifcthvl@sigill.intra.peff.net \
    --to=peff@peff.net \
    --cc=git@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.