From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7B285CA0EE4 for ; Wed, 20 Aug 2025 10:48:22 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uogLn-0002OE-9k; Wed, 20 Aug 2025 06:47:27 -0400 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 1uogLl-0002Ny-Jo for qemu-devel@nongnu.org; Wed, 20 Aug 2025 06:47:25 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uogLi-0004e9-Kw for qemu-devel@nongnu.org; Wed, 20 Aug 2025 06:47:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1755686840; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4T3uE8x8REJmVdBfTwhN+aQ18WSOXNAlm07/HYRwO8Q=; b=PjZyu4N2Ol8/cJMNFdiiTbyQfvD4XCiC2g4bFC2tl3NLwCO7XFgEZMVBdbQ1dLC2GZomCS y35II6EME24rRFzVrKEeI3N70HCKCjQEL4tU7wXjg5TLt7d23Tt2DvTc0dcwla/SxJnTAH CItLOTbDskTRlAKukIR/+aVIN+3J/14= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-594-VYqp0yCwPg-qnhsHVmiORA-1; Wed, 20 Aug 2025 06:47:17 -0400 X-MC-Unique: VYqp0yCwPg-qnhsHVmiORA-1 X-Mimecast-MFC-AGG-ID: VYqp0yCwPg-qnhsHVmiORA_1755686836 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AF46D1802AB7; Wed, 20 Aug 2025 10:47:13 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.164]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id F09E0300019F; Wed, 20 Aug 2025 10:47:09 +0000 (UTC) Date: Wed, 20 Aug 2025 11:47:06 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: "Dr. David Alan Gilbert" Cc: qemu-devel@nongnu.org, Manos Pitsidianakis , Hanna Reitz , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Kevin Wolf , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , devel@lists.libvirt.org, Stefan Weil , qemu-block@nongnu.org, Paolo Bonzini , Markus Armbruster Subject: Re: [PATCH 05/12] util: add API to fetch the current thread id Message-ID: References: <20250819202708.1185594-1-berrange@redhat.com> <20250819202708.1185594-6-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, Aug 19, 2025 at 11:35:26PM +0000, Dr. David Alan Gilbert wrote: > * Daniel P. Berrangé (berrange@redhat.com) wrote: > > For logging it is useful to include the current thread id. On > > POSIX there is no standard API for this, so try the Linux gettid() > > syscall preferentially, otherwise fallback to casting the result > > of thread_self() to an integer. > > > > Signed-off-by: Daniel P. Berrangé > > --- > > include/qemu/thread.h | 1 + > > util/qemu-thread-posix.c | 11 +++++++++++ > > util/qemu-thread-win32.c | 5 +++++ > > 3 files changed, 17 insertions(+) > > > > diff --git a/include/qemu/thread.h b/include/qemu/thread.h > > index 3a286bb3ef..96eee82679 100644 > > --- a/include/qemu/thread.h > > +++ b/include/qemu/thread.h > > @@ -215,6 +215,7 @@ void *qemu_thread_join(QemuThread *thread); > > void qemu_thread_get_self(QemuThread *thread); > > bool qemu_thread_is_self(QemuThread *thread); > > G_NORETURN void qemu_thread_exit(void *retval); > > +uint64_t qemu_thread_get_id(void); > > > > struct Notifier; > > /** > > diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c > > index 121d7ed69b..f240a93632 100644 > > --- a/util/qemu-thread-posix.c > > +++ b/util/qemu-thread-posix.c > > @@ -532,3 +532,14 @@ void *qemu_thread_join(QemuThread *thread) > > } > > return ret; > > } > > + > > +uint64_t qemu_thread_get_id(void) > > +{ > > +#ifdef CONFIG_GETTID > > + return (uint64_t)gettid(); > > +#elif defined(SYS_gettid) > > + return (uint64_t)syscall(SYS_gettid); > > +#else > > + return (uint64_t)pthread_self(); > > My reading of the manpage is that is not guaranteed to be castable. > It also explicitly says it's not the same as gettid. Albeit probably is. Yeah, technically pthread_t could be a struct. Guess it depends how much we care about strict standards portability, vs portability to our tested set of platforms (macOS, *BSD)[1]. We could hardcode to 0 as an alternative. With regards, Daniel [1] admittedly i've not actually compile tested this yet on non-Linux, aside from Windows which uses the non-pthreads code. -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|