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From: Jeff King <>
To: Jeff Hostetler <>
Cc: "Randall S. Becker" <>,, "'SZEDER Gábor'" <>,
	"'Johannes Schindelin via GitGitGadget'" <>,
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: <> (raw)
In-Reply-To: <>

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

> 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).


  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

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