BOINC Computer Summary Page CACHE # ???
7 Sep 2008 0:32:19 UTC
Topic 193903
(moderation:
I just looked at CACHE reported on the Computer Summary page for some of the ATLAS computers I shared WUs with. They showed a cache number of 4 mb. Looking at NewEgg page for those processors matched the 4 mb number. When I look at the NewEgg page for my x5365 processor it says 4 mb also, but the BOINC computer page is only saying 976 kb.
NewEgg doesn't seem to say whether the cache is L1 or L2.
Anyone know just what number BOINC sees? Is it L1 or L2 or sometimes L1 and other times L2? For the x5365 976 kb is neither the L1 nor the L2 number actually.
BOINC Computer Summary Page CACHE # ???
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I have an AMD Opteron 1210 with two cores. BOINC sees L2 memory cache as 1024 KB. But each of my cores has 1024 KB L2 so I really have 2048 KB L2.
Tullio
RE: I just looked at CACHE
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The Intel page for Intel® Xeon® Processor X5365
or the overview for Xeon 5000 Series
L2 cache size 8 MB
The figure reported by BOINC has always been dubious, since day one.
RE: The figure reported by
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Ny Northwood P4 has 512K, but BOINC shows 976ish...
It's an OS-depended value.
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It's an OS-depended value. W2k and XP have problems to check and display correct values, for other MS-OS's i have no experiences. Knoppix, Suse and DSL had never such problems.
You can change the cache-value in registry, but:
L2 Cache Tweak
Alias - SecondLevelDataCache Tweak
Myth - "Adjusting the SecondLevelDataCache Registry value to match your CPU's L2 Cache size improves performance."
Reality - "If you do not set this registry value, Windows will use the HAL (Hardware Abstraction Layer) for retrieval of the L2 cache size automatically on boot up. If this fails, a default value of 256KB is used. This is where the myth that XP can only use 256KB of L2 cache comes from. But it's false. The SecondLevelDataCache is designed as a secondary source of cache size information for computers on which the HAL cannot detect the L2 cache. The HAL is able to retrieve the L2 cache size from any CPU using the set-associative cache design (Pentium II or newer), it's only the relatively few older processors with direct-mapped L2 caches that the HAL will not recognize. This tweak only applies to older computers (Pentium I or older) with over 64 MB of memory. On these older systems, this tweak can improve performance by about 0.4%. Pentium II and later CPUs are not affected."
Source: http://home.comcast.net/~SupportCD/XPMyths.html
Mudlinthru (my laptop) with
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Mudlinthru (my laptop) with an AMD Turion 64 X2 TL-60 processor and Vista SP1, shows a cache size of 488.28 KB on its page here at LHC. Per AMD, the chip has 1 MB of L2 cache per core, 2 MB total. If it's trying to display the L2 cache size and the value displayed is an OS-depended value, the reporting of it is still not corrected in Vista SP1.
Cheers,
Stephen
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II If something can go wrong, it will.
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