From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: Some experience with the igc branch Date: Fri, 27 Dec 2024 17:28:53 +0200 Message-ID: <86cyhdw3ey.fsf@gnu.org> References: <87o713wwsi.fsf@telefonica.net> <86zfkjznat.fsf@gnu.org> <86ldw2zy6s.fsf@gnu.org> <87h66p5fy6.fsf@protonmail.com> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="4644"; mail-complaints-to="usenet@ciao.gmane.io" Cc: gerd.moellmann@gmail.com, stefankangas@gmail.com, ofv@wanadoo.es, emacs-devel@gnu.org, eller.helmut@gmail.com, acorallo@gnu.org To: Pip Cet Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Fri Dec 27 16:29:40 2024 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1tRCHT-00013X-EO for ged-emacs-devel@m.gmane-mx.org; Fri, 27 Dec 2024 16:29:39 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tRCGy-0003yB-KS; Fri, 27 Dec 2024 10:29:08 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tRCGp-0003uB-5N for emacs-devel@gnu.org; Fri, 27 Dec 2024 10:29:00 -0500 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tRCGo-0002WI-0C; Fri, 27 Dec 2024 10:28:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=References:Subject:In-Reply-To:To:From:Date: mime-version; bh=UAWb0+GfEuQT4paF/DI+jugy6vvq4R/lA+uXRKoA41w=; b=ok1e1DtY3reC 3eBaMP2fw6N3+UFr/v+Y9XL3UNtOFUSr8iUE6zbl7c7Yo3qgt8iJWElQOKyU+SEFipQDB84tGVKTS adriwZ4ARZu3j7PtOJowrVHuZs5DdaY7gWuH3HSWLUSpjV9gDKeKuiBGT+L8eg9wLTTmZ4NzWqzXr uD2y/MhHgCltVCCMjZDkq4v17Bfq/xycuLsDgKEseXZRe9X5yRRHEKeg9v4YICV/p0tSR+VUwvZMh u1McRP88GDhxw4/tva2DkuAnu9poHK3Bkwnwhh30mUJXF7hpPOAu/K/t2kJeBzGdUAI0MCGViJFYe 83iXnth19x9O+6LCr45Kpg==; In-Reply-To: <87h66p5fy6.fsf@protonmail.com> (message from Pip Cet on Fri, 27 Dec 2024 15:01:11 +0000) X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:327204 Archived-At: > Date: Fri, 27 Dec 2024 15:01:11 +0000 > From: Pip Cet > Cc: Stefan Kangas , Eli Zaretskii , ofv@wanadoo.es, emacs-devel@gnu.org, eller.helmut@gmail.com, acorallo@gnu.org > > > - Concurrent. The GC runs in its own thread. There are no explicit > > calls to start GC, and Emacs doesn't have to wait for the GC to > > complete. > > I don't think that's true right now (it is what I want for Christmas, > though). On GNU/Linux, the GC usually runs on the main thread. Isn't it both, actually? That is, MPS could be triggered both synchronously and on a separate thread? That's what I thought. At least on Windows, I clearly see new threads starting when MPS starts GC. > On > macOS, the GC can run on the main thread (allocation) or on the SIGSEGV > handler thread (memory barriers); in both cases, the main thread has to > wait for it to complete. > > I'm not sure it's ever useful to make the assumption that GC isn't > concurrent: it is very hard to do so, but it is possible. > > Maybe Eli knows more; I posted a patch to force concurrent GC for > debugging a while ago, and Eli told me not to because it would produce > false positives. I'm not so sure about the "false" part now. I just conveyed what a comment in igc.c says (or used to say back in May).