git.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Jeff King <peff@peff.net>
To: Jeff Hostetler <git@jeffhostetler.com>
Cc: "Randall S. Becker" <rsbecker@nexbridge.com>,
	git@vger.kernel.org, "'SZEDER Gábor'" <szeder.dev@gmail.com>,
	"'Johannes Schindelin via GitGitGadget'" <gitgitgadget@gmail.com>,
	jeffhost@microsoft.com
Subject: Re: [BUG] Unix Builds Requires Pthread Support (was [PATCH v4 00/12] Simple IPC Mechanism)
Date: Tue, 18 May 2021 08:11:48 -0400	[thread overview]
Message-ID: <YKOvBGjAC2kVPVa7@coredump.intra.peff.net> (raw)
In-Reply-To: <8540e41e-3ba6-8d40-9424-8f62ea785f42@jeffhostetler.com>

On Tue, May 18, 2021 at 07:21:33AM -0400, Jeff Hostetler wrote:

> > In the simple-ipc API, there's an explicit "async" interface. But it's
> > not clear to me how rich it expects the communication with the caller to
> > be (i.e., whether we could get away with the fork() trick here). Or if
> > it would be OK for the threading to remain an implementation detail,
> > with one "worker" upon whom we wait for completion.
> > 
> 
> TBH I forgot that we still support NO_PTHREAD systems.
> I seem to remember that we got rid of some of the non-pthread
> stub functions at one point, but I'm fuzzy on the details.

You're probably thinking of when we got rid of a bunch of #ifdef code
paths in index-pack, and replaced it with stubs that turn the pthread
calls into "do nothing" (so all the ugly stuff is in thread-utils.h
now). But we still very much support systems that don't handle pthreads
at all.

> WRT to "simple ipc" (and future "builtin fsmonitor"), it's heavily
> threaded.  There's no point in trying to fake it with forks.
> 
> The server side of simple ipc implements a thread pool.  And
> the builtin fsmonitor will use a thread to monitor FS events
> and that thread pool to respond to clients.  All driven from a
> shared queue of events.
> 
> It would be a major overhaul to do all that without threads
> -- and even that assumes that nonstop has a sufficient file
> system notification mechanism.

OK, that matches my guess from a brief look at the code. Thanks for
confirming.

> So, yes, we should ifdef it out as Peff suggests.

The patch I sent wasn't really tested beyond confirming that "make
NO_PTHREADS=1" finished compiling (and that test-tool simple-ipc
barfed appropriately at runtime).

Do you want to pick it up from there and produce a polished patch? I
think we should deal with this prior to the v2.32.0 release (and thanks
Randall for testing and finding it during the -rc0 period).

-Peff

  reply	other threads:[~2021-05-18 12:11 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-17 17:46 Randall S. Becker
2021-05-18  8:23 ` Jeff King
2021-05-18 11:21   ` Jeff Hostetler
2021-05-18 12:11     ` Jeff King [this message]
2021-05-18 13:55       ` Jeff Hostetler
2021-05-18 13:37   ` Randall S. Becker
2021-05-18 13:59     ` Jeff King

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=YKOvBGjAC2kVPVa7@coredump.intra.peff.net \
    --to=peff@peff.net \
    --cc=git@jeffhostetler.com \
    --cc=git@vger.kernel.org \
    --cc=gitgitgadget@gmail.com \
    --cc=jeffhost@microsoft.com \
    --cc=rsbecker@nexbridge.com \
    --cc=szeder.dev@gmail.com \
    --subject='Re: [BUG] Unix Builds Requires Pthread Support (was [PATCH v4 00/12] Simple IPC Mechanism)' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).