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Unread postPosted: Sun Dec 04, 2011 10:26 pm 
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Joined: Wed Nov 12, 2008 9:02 pm
Posts: 75
Location: Tempe, Arizona
sbarton wrote:
I think the biggest factor is that supersparc can issue 3 instructions vs 2 for the hypersparc. Also the cache (I think) on the ross setup shares 1M for each module but at 2:1, where as supersparcs have a 1:1 cache ratio.

Probably on single threaded tasks like compiling or setting up a box for some paticular service (ftp/mail gateway/etc) the ROSS configuration makes sense. I use my SS20 more for just piddling around with the typical desktop setup, so X11, blackbox/CDE, xmms, a few glib programs (which really stress the platform), etc...so again, heavily threaded and lots of context switching.

I would really like to experiance a sparcserver 1000e with 8 SM8/91s


The quad 142s have 4x 1MB.

The numbers don't add up (i.e. an over simplified calculation like 3*85 vs 2*142), the HyperSparc should at least match the SS and usually well exceed it because the amount of ILP going on wont be 100%, especially on an in-order CPU.

I've been digging around the NetBSD code and it looks like the HS might dump all cache on context switches(?!) which would murder performance, but maybe I understood the code wrong or it's a NetBSD specific hack.

Another quite probable explanation is that the compiler optimizations in Solaris favored SS.

Not that SS isn't awesome, I just think something must be fundamentally wrong for what are essentially much newer hotrod/upgrade processors (142/1M, 180/512, 200/512) to be slower in common usage.

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Unread postPosted: Mon Dec 05, 2011 6:28 pm 
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Joined: Wed Aug 26, 2009 9:55 am
Posts: 145
Well, thats just it. It's not a newer processor at all. All of the ROSS CPUs where Hypersparc derivatives. SUPERSparc has almost twice the transistor count and is a more advanced processor in almost every respect. Even the cache is more advance (beyond just the amount and clock speed). The idea with the ROSS processors was that with the lower transistor count, the clock speed was able to be pushed higher. So again, for many server based tasks, which is basically what your typical SS20 was used for in those days, it may have paid off, I don't know.


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