Ping :-) On Oct 28, 2016 18:48, "Luca Boccassi" <[email protected]> wrote:
> I have sent a solution for the alignment problem that solves the sigbus > problem without breaking ABI compat (plus follow-up for VC++ - sorry > Windows guys https://github.com/zeromq/libzmq/pull/2179 ). > > I tested the alignment and sigbus problem on x86_64 by enabling > alignment check with: > > __asm__("pushf\norl $0x40000,(%rsp)\npopf"); > > All was fine. > > I ran tests built from the zeromq4-1 repository against a shared lib > from the head of libzmq repo, and they all run fine minus the > ZMQ_REQ_CORRELATE one but that option was borken anyway. > > This allows us to do a release now, and then when we are ready we can do > the ABI breakage, without blocking 4.2. Which is nice since it means it > might make it for Debian 9! > > So, Doron et al, shall we do the bump this weekend? > > On Thu, 2016-10-20 at 17:12 -0500, Thomas Rodgers wrote: > > I will have some time most likely the week of Nov6 (off for a week of C++ > > Committee 'fun') to test different message size alternatives. I'll follow > > up with my results here for consideration the next time we are inclined > to > > break the ABI compatibility :) > > > > On Sunday, October 16, 2016, Brian Knox <[email protected]> wrote: > > > > > A new stable version would definitely help me in my quest to get ZeroMQ > > > support enabled by default in rsyslog in distros. > > > > > > On Sun, Oct 16, 2016 at 2:40 PM Doron Somech <[email protected]> > wrote: > > > > > >> I say lets bump. > > >> > > >> On Oct 15, 2016 20:32, "Luca Boccassi" <[email protected]> > wrote: > > >> > > >>> As Thomas said, false sharing would be a real issue with 96. > > >>> > > >>> So given a release is long due, at this point I'd say to drop this > for > > >>> the moment. > > >>> > > >>> What do we do for the change to union for zmq_msg_t? Bump ABI > version or > > >>> not? > > >>> > > >>> On Thu, 2016-10-06 at 09:53 +0300, Doron Somech wrote: > > >>> > No new socket type, I worked at the time on binary message type, > might > > >>> > complete it sometime, but it is not urgent. > > >>> > > > >>> > If there is a lot of performance penalty we can give it up, I will > > >>> > find another solution for the Radio-Dish. > > >>> > > > >>> > What about 96 bytes? same penalty? > > >>> > > > >>> > Regarding the binding, I'm not sure. > > >>> > > > >>> > On Sat, Oct 1, 2016 at 9:14 PM, Luca Boccassi < > [email protected]> > > >>> wrote: > > >>> > > On Tue, 2016-09-27 at 09:41 +0300, Doron Somech wrote: > > >>> > >> Sorry for the late response, increasing the msg_t structure > will be > > >>> > >> great, however this will require changing a lot of binding. > > >>> > > > > >>> > > I think I remember we need it for the new socket types, is that > > >>> correct? > > >>> > > > > >>> > > There is a large performance penalty (intuitively due to not > fitting > > >>> > > into a single cache line anymore, but haven't ran > perf/cachegrind), > > >>> and > > >>> > > the throughput with vsm type messages goes down by 4% (min) and > 20% > > >>> > > (max) for TCP, and 36% (min) 38 (max) for inproc, which is quite > a > > >>> lot, > > >>> > > so we need to be sure it's worth it. > > >>> > > > > >>> > > Regarding the bindings, after a quick search on the Github org, I > > >>> could > > >>> > > only see: > > >>> > > > > >>> > > https://github.com/zeromq/lzmq/blob/master/src/lua/lzmq/ > > >>> ffi/api.lua#L144 > > >>> > > https://github.com/zeromq/clrzmq4/blob/master/lib/zmq.cs#L28 > > >>> > > https://github.com/zeromq/pyczmq/blob/master/pyczmq/zmq.py#L177 > > >>> > > > > >>> > > Other bindings just import zmq.h. Did I miss any? > > >>> > > > > >>> > >> Sorry for disappearing, baby and full time job is a lot :-), > > >>> hopefully > > >>> > >> I'm back... > > >>> > > > > >>> > > No worries, perfectly understandable :-) > > >>> > > > > >>> > >> On Mon, Aug 29, 2016 at 6:46 PM, Luca Boccassi < > > >>> [email protected]> wrote: > > >>> > >> > Sorry, I meant if we go with (1), not (2), we might bump the > size > > >>> as > > >>> > >> > well, since we are already doing another ABI-breaking change. > > >>> > >> > > > >>> > >> > I agree on the solution as well. > > >>> > >> > > > >>> > >> > On Mon, 2016-08-29 at 17:12 +0200, Pieter Hintjens wrote: > > >>> > >> >> I'm confused between the (1) and (2) choices, and can't see > where > > >>> > >> >> bumping the message size fits. > > >>> > >> >> > > >>> > >> >> Nonetheless, I think bumping the size, fixing the alignment > > >>> issues, > > >>> > >> >> and bumping the ABI version is the best solution here. > > >>> > >> >> > > >>> > >> >> On Fri, Aug 26, 2016 at 12:33 PM, Luca Boccassi < > > >>> [email protected]> wrote: > > >>> > >> >> > I've given some more thoughts and testing to the alignment > > >>> issue. I can > > >>> > >> >> > reproduce the problem by enabling alignment checks on x86 > too. > > >>> > >> >> > > > >>> > >> >> > But most importantly, I think we cannot get away from > bumping > > >>> the ABI > > >>> > >> >> > with this fix, however we rearrange it, simply because > > >>> applications need > > >>> > >> >> > to be rebuilt against the new header to be fixed. A simple > > >>> rebuild of > > >>> > >> >> > the libzmq.so is not enough. And the way to do this is to > bump > > >>> the ABI > > >>> > >> >> > so that distros can schedule transitions and rebuilds and > so > > >>> on. > > >>> > >> >> > > > >>> > >> >> > So the choice list is now restricted to: > > >>> > >> >> > > > >>> > >> >> > 1) Bump ABI > > >>> > >> >> > 2) Revert the fix and leave everything broken on sparc64 > and > > >>> some > > >>> > >> >> > aarch64 (rpi3 seems not to be affected, must depend on the > SoC > > >>> flavour) > > >>> > >> >> > > > >>> > >> >> > If we go with 2, we might as well get 2 birds with one > stone > > >>> and bump > > >>> > >> >> > the zmq_msg_t size to 128 as we have talked about in the > past. > > >>> > >> >> > > > >>> > >> >> > Doron, this would help with the new UDP based socket types > > >>> right? > > >>> > >> >> > > > >>> > >> >> > Pros of bumping msg size: > > >>> > >> >> > > > >>> > >> >> > - we can get rid of the malloc() in the lmsg type case as > all > > >>> the data > > >>> > >> >> > will fit > > >>> > >> >> > > > >>> > >> >> > Cons: > > >>> > >> >> > > > >>> > >> >> > - for the vsm/cmsg type cases (for most architectures > anyway) > > >>> it won't > > >>> > >> >> > fit anymore into a single cacheline > > >>> > >> >> > > > >>> > >> >> > Given all this, I'd say we should go for it. > > >>> > >> >> > > > >>> > >> >> > Opinions? > > >>> > >> >> > > > >>> > >> >> > On Sat, 2016-08-13 at 16:59 +0100, Luca Boccassi wrote: > > >>> > >> >> >> Hello, > > >>> > >> >> >> > > >>> > >> >> >> Trying to give some thoughts again on the libzmq 4.2 > release. > > >>> It's > > >>> > >> >> >> really long overdue! > > >>> > >> >> >> > > >>> > >> >> >> The main issue from my point of view is this change: > > >>> > >> >> >> > > >>> > >> >> >> https://github.com/zeromq/libzmq/commit/ > > >>> d9fb1d36ff2008966af538f722a1f4ab158dbf64 > > >>> > >> >> >> > > >>> > >> >> >> -typedef struct zmq_msg_t {unsigned char _ [64];} > zmq_msg_t; > > >>> > >> >> >> +/* union here ensures correct alignment on architectures > > >>> that require > > >>> > >> >> >> it, e.g. > > >>> > >> >> >> + * SPARC > > >>> > >> >> >> + */ > > >>> > >> >> >> +typedef union zmq_msg_t {unsigned char _ [64]; void *p; > } > > >>> zmq_msg_t; > > >>> > >> >> >> > > >>> > >> >> >> > > >>> > >> >> >> This is flagged by the common ABI checkers tools as an ABI > > >>> breakage > > >>> > >> >> >> (see: http://abi-laboratory.pro/tracker/timeline/zeromq/ > ). > > >>> And it makes > > >>> > >> >> >> sense from this point of view: if some applications on > some > > >>> > >> >> >> architectures are broken due to wrong alignment, they > would > > >>> need to be > > >>> > >> >> >> rebuilt, and the way to ensure that is to bump the ABI > > >>> "current" digit > > >>> > >> >> >> to make sure maintainers do a rebuild. > > >>> > >> >> >> > > >>> > >> >> >> On the other hand, signaling an ABI breakage is a pain, > and a > > >>> cause of > > >>> > >> >> >> major churn for packagers and maintainers. It means for > > >>> example a new > > >>> > >> >> >> package has to be created (eg: libzmq5 -> libzmq6), and a > > >>> transition has > > >>> > >> >> >> to be started and all reverse dependencies need to be > > >>> rebuilt. And if > > >>> > >> >> >> this is pointless for all save a few corner cases (eg > SPARC64 > > >>> as for > > >>> > >> >> >> above) it's all quite frustrating. > > >>> > >> >> >> > > >>> > >> >> >> So we have a choice to make before we release 4.2, four > > >>> possibilities as > > >>> > >> >> >> far as I can see: > > >>> > >> >> >> > > >>> > >> >> >> 1) Ignore the ABI checkers and get yelled at by > maintainers > > >>> and > > >>> > >> >> >> packagers. Also the SPARC64 users will most likely NOT get > > >>> their bug > > >>> > >> >> >> fixed > > >>> > >> >> >> 2) Bump ABI revision to 6 and get yelled at by maintainers > > >>> and packagers > > >>> > >> >> >> 3) Revert the above change and postpone it to when we > have a > > >>> more > > >>> > >> >> >> generally useful reason to break ABI (bump zmq_msg_t from > 64 > > >>> to 128 > > >>> > >> >> >> bytes for example, Doron?) > > >>> > >> >> >> 4) Try to be clever and revert the above change and use > > >>> something like > > >>> > >> >> >> #pragma pack(8). This will fool the ABI checkers (I tried > > >>> it), and given > > >>> > >> >> >> that typedef is only used externally to allocate the right > > >>> size it > > >>> > >> >> >> shouldn't actually affect anything, apart from the users > of > > >>> SPARC64 > > >>> > >> >> >> which should get the bugfix with this too. This is very > > >>> sneaky :-) > > >>> > >> >> >> > > >>> > >> >> >> CC'ing Lazslo, the Debian maintainer, given what we > choose to > > >>> do might > > >>> > >> >> >> result in a lot of work for him :-) > > >>> > >> >> >> > > >>> > >> >> >> Opinions? > > >>> > >> >> >> > > >>> > >> >> >> Kind regards, > > >>> > >> >> >> Luca Boccassi > > >>> > >> >> >> > > >>> > >> >> >> On Tue, 2016-05-03 at 10:39 +0200, Pieter Hintjens wrote: > > >>> > >> >> >> > Hi all, > > >>> > >> >> >> > > > >>> > >> >> >> > I'm just throwing some ideas on the table. We have a > good > > >>> package of > > >>> > >> >> >> > work on master and it's probably time to make a 4.2 > release. > > >>> > >> >> >> > > > >>> > >> >> >> > Luca has already back-ported the enable/disable draft > > >>> design from > > >>> > >> >> >> > zproject (CZMQ et al). Yay! So we can now release stable > > >>> master > > >>> > >> >> >> > safely, while continuing to refine and extend the draft > API > > >>> sections. > > >>> > >> >> >> > > > >>> > >> >> >> > I propose: > > >>> > >> >> >> > > > >>> > >> >> >> > - to end with the stable fork policy; this was needed > years > > >>> ago when > > >>> > >> >> >> > we had massively unstable masters. It's no longer a > problem. > > >>> > >> >> >> > - to use the github release function for libzmq releases > > >>> and deprecate > > >>> > >> >> >> > the separate delivery of tarballs. > > >>> > >> >> >> > - we aim to make a 4.2.0 rc asap, then fix any issues we > > >>> get, with > > >>> > >> >> >> > patch releases as usual. > > >>> > >> >> >> > - we backport the release function to older maintained > > >>> releases (4.1, > > >>> > >> >> >> > 3.2) so that their tarballs are provided by github > instead > > >>> of > > >>> > >> >> >> > downloads.zeromq.org. > > >>> > >> >> >> > > > >>> > >> >> >> > Problems: > > >>> > >> >> >> > > > >>> > >> >> >> > - this will break a few things that depend on > > >>> downloads.zeromq.org. To > > >>> > >> >> >> > be fixed as we go. > > >>> > >> >> >> > - github tarballs are not identical to source tarballs, > > >>> particularly > > >>> > >> >> >> > they lack `configure`. I propose changing our autotools > > >>> build > > >>> > >> >> >> > instructions so they always start with `./autogen,sh` no > > >>> matter where > > >>> > >> >> >> > the sources come from. > > >>> > >> >> >> > > > >>> > >> >> >> > I think this will work and also let us gracefully > > >>> deprecate/switch off > > >>> > >> >> >> > the downloads box. > > >>> > >> >> >> > > > >>> > >> >> >> > -Pieter > > >>> > >> >> >> > _______________________________________________ > > >>> > >> >> >> > zeromq-dev mailing list > > >>> > >> >> >> > [email protected] > > >>> > >> >> >> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev > > >>> > >> >> >> > > >>> > >> >> >> > > >>> > >> >> > > > >>> > >> >> > > > >>> > >> >> > > > >>> > >> >> > _______________________________________________ > > >>> > >> >> > zeromq-dev mailing list > > >>> > >> >> > [email protected] > > >>> > >> >> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev > > >>> > >> >> _______________________________________________ > > >>> > >> >> zeromq-dev mailing list > > >>> > >> >> [email protected] > > >>> > >> >> http://lists.zeromq.org/mailman/listinfo/zeromq-dev > > >>> > >> > > > >>> > >> > > > >>> > > > > >>> > > >>> _______________________________________________ > > >> zeromq-dev mailing list > > >> [email protected] > > >> http://lists.zeromq.org/mailman/listinfo/zeromq-dev > > > > > > > > _______________________________________________ > > zeromq-dev mailing list > > [email protected] > > http://lists.zeromq.org/mailman/listinfo/zeromq-dev > > >
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