The IBM POWER8 Review: Challenging the Intel Xeon
by Johan De Gelas on November 6, 2015 8:00 AM EST- Posted in
- IT Computing
- CPUs
- Enterprise
- Enterprise CPUs
- IBM
- POWER
- POWER8
Trying Out a Different Compiler: IBM's XLC
Based on our previous results the IBM POWER8 has definitely attracted our interest, and we were motivated to test a lot more. Can IBM's own compiler "XLC" boost the scores even more?
To test that out, we joined the IBM OpenPOWER Linux community and downloaded the IBM XLC compiler. We compiled with two different and rather aggressive settings:
- -qhot -O4 -qarch=pwr8
- -qhot -O5 -qarch=pwr8
We've taken our XLC binaries and set them up against binaries compiled with GCC 4.9.2 using the "-o3 -mcpu=power8" flag. The mcpu=power8 flag has very little impact on performance, but we wanted to be sure that GCC was given every opportunity to optimize for the POWER8 CPU.
The results for XLC are very weird. Using the -O4 flag the XLC compiler does pretty badly on compression (-7%), while increasing performance by 7% in decompression. Nothing to write home about. Only when we use the -O5 flag do we get an increase in performance by 7-8%. However we also found that -O5 was too aggressive for most complex software that we ported to the POWER8, and as a result isn't very usable.
We suspect that the XLC compiler for LE Linux is still a bit immature and has still some room to improve. Which unfortunately isn't doing IBM any favors at this moment since XLC is a paid compiler.
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JohanAnandtech - Saturday, November 7, 2015 - link
Ok, Europe adopt the dot, but maybe the US can adopt the metric system like the rest of the world? :-)bitaljus - Saturday, November 7, 2015 - link
or better yet recode this site to see from what country u are visiting and use the appropriate denote thousands symbol, appropriate metric system and even time for the viewer. how meany time i was irradiated when i need to google something like this just to make it in local. and this is easy to do in the site natively. (P.S. Sorry for bad English, not native)nils_ - Wednesday, November 11, 2015 - link
The browser already sends a header with Accept-Language, which should be the preferred way to for the web site to determine locale. For example, I live in Germany so my browser will send en, en_UK, en_US, de and DE (this can be set somewhere in the settings). Now you can determine the language and other localisation based upon that, and there are tools where you can set the locale to then display dates, times etc.. based n that.Many sites instead use Geolocation based on the IP address, which can be really awkward when you travel to a country where you can't read the language.
ZeDestructor - Saturday, November 7, 2015 - link
Even within EU it's not consistent.. UK uses commas for thousands, dot for decimal (and that's why the US and most anglophone countries use the same setup), Germany, Netherlands and France on the other hand favour dots for thousands, commas for decimal, so you see it used there.. and in a great number of their former colonies where the language and culture has stuck.nils_ - Wednesday, November 11, 2015 - link
Dates / Time are even funnier, that's also extremely inconsistent and can be very misleading. Think for examle a date like 12/11/2015, in some countries it'll mean the 12th of November while in others it will mean the 11th of December, and sometimes even the 2015th of November in 11 AD ;)I remember reading on the GTA IV in-game "Internet" a travel guide to Europe that said the months here have 12 days but there are 30 months a year or something to that effect ;)
powchie - Friday, November 6, 2015 - link
let Johan do more reviews. been reading his stuff from late 90's and consider him the best then followed by Anand.Ryan Smith - Saturday, November 7, 2015 - link
Trust me when I say that if I could whip Johan any harder and make him work any faster I would be doing just that.;-)juhatus - Saturday, November 7, 2015 - link
When the Balrog showed up for work he had everyone fired.ruthan - Friday, November 6, 2015 - link
In summary should be something about software support, raw power is here, but software stack isvery limited.
PowerCPU is good for old legacy apps - SAP, Oracle etc.. but otherwise its dead end.
I would like to see comparision of IBM LPAR virtualization against Xeon Vmware solution, or Oracle / MySQL benchmark on power vs. Oracle benchmark on Xeon.
Server with Power even cant to run Crysis, or maybe some QEMU magic..
ruthan - Friday, November 6, 2015 - link
Pleas Ad edit button like other civilized sites, i was hurry when i wrote it.