From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:35795) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Si30X-0001hQ-Vw for qemu-devel@nongnu.org; Fri, 22 Jun 2012 08:30:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Si30W-0003DM-7g for qemu-devel@nongnu.org; Fri, 22 Jun 2012 08:30:37 -0400 Received: from mail-bk0-f45.google.com ([209.85.214.45]:46667) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Si30W-0003DD-0n for qemu-devel@nongnu.org; Fri, 22 Jun 2012 08:30:36 -0400 Received: by bkwj10 with SMTP id j10so1599051bkw.4 for ; Fri, 22 Jun 2012 05:30:33 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1340347459-29861-1-git-send-email-peter.crosthwaite@petalogix.com> <4FE423B0.9020702@siemens.com> Date: Fri, 22 Jun 2012 13:30:32 +0100 Message-ID: From: Peter Maydell Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [RFC] block: Removed coroutine ownership assumption List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: kwolf@redhat.com, stefanha@linux.vnet.ibm.com, Jan Kiszka , qemu-devel@nongnu.org, Peter Crosthwaite , edgar.iglesias@gmail.com, john.williams@petalogix.com On 22 June 2012 13:04, Markus Armbruster wrote: > Peter Maydell writes: > >> On 22 June 2012 09:48, Markus Armbruster wrote: >>> In my opinion, coroutines have been useful for us so far. =C2=A0Whether= they >>> remain useful, or serve us just as a stepping stone towards general >>> threads remains to be seen. >> >>>>From my point of view I've seen a whole pile of problems and not >> really any advantages... > > Advantages over what? Over what we had before we had coroutines. I know there are advantages, I'm just saying that personally I've been largely on the downside rather than the upside. >> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0I particularly think it's a really bad >> idea to have a complex and potentially race-condition-prone bit >> of infrastructure implemented three different ways rather than >> having one implementation used everywhere -- it's just asking >> for obscure bugs on the non-x86 hosts. > > Fair point, but it's an implementation problem, not a fundamental > problem with coroutines. =C2=A0You *can* implement coroutines portably, > e.g. on top of gthread. If you're implementing them on top of separate threads then you just have an obfuscated API to threads. -- PMM