----- On Sep 27, 2015, at 7:20 PM, Mathieu Desnoyers [email protected] wrote:
> ----- On Mar 12, 2014, at 8:29 AM, Mathieu Desnoyers > [email protected] wrote: > >> ----- Original Message ----- >>> From: "Dimitri John Ledkov" <[email protected]> >>> To: [email protected] >>> Cc: [email protected], "mathieu desnoyers" >>> <[email protected]> >>> Sent: Wednesday, March 12, 2014 7:26:12 AM >>> Subject: RE: [lttng-dev] Support for new arch 'ppc64le' >>> >>> (sorry for breaking threading, I was not previously subscribed) >>> >>> On 03/12/2014 12:58 AM, Mathieu Desnoyers wrote: >>> > I see that the patch you propose adds both "powerpc64le" and "aarch64" >>> > entries. Why are there two of them? >>> >>> Currently there are two fairly recent architectures, which at the >>> moment can only be compiled with "gcc atomics" code path. >>> The two new architectures are (GNU Types): >>> * aarch64-linux-gnu (aka ARMv8, ARM64, AARCH64, etc) >>> * powerpc64le-linux-gnu >>> >>> Upstream config.guess/config.sub/libtool/kernel/compilers have support >>> for these targets and many distributions are bootstrapping/building >>> archives for these architectures. Although for complete support, >>> ideally one would create tarballs on systems with patched libtool, >>> it's not required for distributions since we have support to update >>> config.guess/config.sub/libtool at package build time. >>> >>> Thus I'd like to only request for aarch64/powerpc64el to be recognized >>> as archtypes that use gcc atomics in configure.ac. See attached patch. >> >> OK. My request to you is that there has been some testing (make check, >> make regtest and ensuring there is no crash, assertions, or other issues >> reported) on each of those architectures with userspace RCU. >> >>> >>> Alternatively, you might want to consider making "gcc" atomics the >>> fallback ARCHTYPE, instead of "unknown" such that compilation of this >>> package is at least attempted on unexpected architectures. >> >> The reason why we don't have this fallback is because we want to make sure >> the implementation of gcc atomics are tested for each architecture before >> we allow building userspace RCU for them. You may call us paranoid over >> this, but we just don't trust the compiler to always do the right thing. >> >> I'll merge your patch into master. However, since this can be considered >> as new features (and not bugfixes), I cannot backport it to the stable >> branches of userspace RCU. So it will be in there for the future 0.9 >> branch. > > Hi, > > I'm currently trying out userspace RCU on a POWER8, and I was wondering > why we use the "gcc" arch fallback for powerpc64le ? I'll move powerpc64le to "ppc" to wire up the membarrier system call in the master branch of urcu. Let me know if this can be an issue. Thanks! Mathieu > > Commit 3913336f0e states > > " Currently there are two fairly recent architectures, which at the > moment can only be compiled with "gcc atomics" code path. > The two new architectures are (GNU Types): > * aarch64-linux-gnu (aka ARMv8, ARM64, AARCH64, etc) > * powerpc64le-linux-gnu" > > I tried changing "gcc" for "ppc" in configure.ac for powerpc64le, > and so far it seems to build and run fine. But considering the > commit message above, there seems to be some unidentified reason > for using the "gcc" fallback rather than the powerpc-specific > implementation of memory barriers and atomic ops in urcu. > > Do you have further information on this ? > > Thanks, > > Mathieu > >> >> Thanks, >> >> Mathieu >> >>> >>> -- >>> Regards, >>> >>> Dimitri. >>> >> >> -- >> Mathieu Desnoyers >> EfficiOS Inc. >> http://www.efficios.com >> >> _______________________________________________ >> lttng-dev mailing list >> [email protected] >> http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev > > -- > Mathieu Desnoyers > EfficiOS Inc. > http://www.efficios.com -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
