Date: Mon, 8 Dec 2014 04:43:05 -0500 From: grarpamp <grarpamp@gmail.com> To: freebsd-hardware@freebsd.org Cc: freebsd-performance@freebsd.org, freebsd-smp@freebsd.org, freebsd-questions@freebsd.org Subject: HyperThreading on Intel Xeon Haswell, a benefit? Message-ID: <CAD2Ti28LZD6u%2BAovBHBFUjQGe0yQLEeArx1t-09sWHTPvOCcpw@mail.gmail.com>
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HyperThreading on Intel Xeon Haswell, a benefit? What bits of FreeBSD are aware and can take proper advantage of Intel HTT, such as its thread/process schedulers (sched-BSD/ULE/...), etc? What system/app loads are, or are not, likely to benefit with today's HyperThreading CPU's? Kernel (ZFS/crypto/net/...) vs. Userland (apps)? Does anyone have performance stats for this current class of CPU to post comparing HT (enabled and disabled) while using more than four processes/threads in parallel? For instance, these two Intel Xeon Haswell four core CPU's are identical except for HT [1] (e3-1226v3 and e3-1246v3), and you can always turn HT off for testing. http://ark.intel.com/compare/80917,80916 There are some Core i3/i5/i7 Haswell parts with HT as well. http://ark.intel.com/Search/Advanced?s=t&ECCMemory=true&VTD=true&AESTech=true There don't seem to be many reviews of Xeon processors, let alone HT. And most Unix talk of HT seems dated by at least a few years and a couple processor generations. Also, was the HT cache leak security issue from a decade ago ever fixed in hardware? "Cache missing for fun and profit" http://www.daemonology.net/papers/ Being unsure of the best list, please direct replies to whichever is good. Thanks. [1] Plus 200MHz/6% clock per core and $59/27% market price bumps, but this thread is about whether or not there is any benefit to HT in current Intel CPU's such as Haswell, how much of one, and where. Once that is determined, then you can factor in other parameters like these to see if it's an overall value.
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