Hello, On Tue, Mar 03 2020, David C. Rankin wrote:
On 02/29/2020 07:00 AM, Frans de Boer wrote:
LS,
Just installed the beta version of leap15.2, just to see if there is anything too upgrade for. Nope, just a new kernel and may some other new or updated packages, but even glibc stays ancient, just as many other packages. Thus keeping leap15.2 as slow as leap15.1 which is 4 times slower then TW for mathematics due to the ancient glibc library and possible the very ancient gcc tool set.
Feel free to install a newer gcc from https://build.opensuse.org/project/show/devel:gcc
But, maybe I am pessimistic and can someone correct me?
Chuckling.... can somebody correct you?
That's a very difficult question to answer. However, there are some observations to be made, "slower" and "faster" are qualitative and 4 times a qualitative measure is still itself qualitative.
Can you include some specific benchmarks you are referring to? The reason being, is I haven't seen any great leap in performance tied to glibc that I can think of.
From release notes of glibc 2.27:
* Optimized x86-64 asin, atan2, exp, expf, log, pow, atan, sin, cosf, sinf, sincosf and tan with FMA, contributed by Arjan van de Ven and H.J. Lu from Intel. * Optimized x86-64 trunc and truncf for processors with SSE4.1. * Optimized generic expf, exp2f, logf, log2f, powf, sinf, cosf and sincosf.
From release notes of glibc 2.29:
* Optimized generic exp, exp2, log, log2, pow, sinf, cosf, sincosf and tanf. About a year ago I was comparing 2.26 from SLES 15.0 and 2.29(*) on SPEC FPrate 2017 using gcc 9.1 (rc) on a Zen1-based AMD CPU. At -Ofast and with -march=native: - 521.wrf improved by 29% - 227.cam4 improved by 26% - 544.nab_r improved by 13.3% - 554.roms_r improved by almost 9% At -O2 (not a very good optimization level for SPEC rate) and generic march/mtune 503.bwases improved by 42%(!). It should not be difficult to construct a synthetic benchmark that would be 4x as fast with current glibc compared to 2.26 - just benchmark repeated invocations of exp :-) Some of these improvements - some of those coming from glibc 2.27 - were backported to SLE 15.1 and thus to leap 15.1. Unfortunately, the second batch was also quite significant and is not present in Leap glibc. (*) This 2.29 glibc also had a backport of /usr/include/finclude/math-vector-fortran.h which IIRC is upstream only since glibc 2.30. To make use of it, you need gcc 9.1 or newer.
Were it not for the cessation of updates, I could happily still be running 11.0 and the performance of assembly, C, C++ would still be very comparable. (though STL availability would be a problem)
I have repeatedly measured that a lot of CPU-intensive code produced with more modern toolchain has significantly better performance in the last few years, let alone since 11.0. Martin -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org