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We currently use the traditional SI-like prefixes to represent binary multipliers in some contexts. This is ambiguous in many cases since they overload the meaning of the SI prefix. Here are some examples of commonly used in the industry: * Storage vendors define 1 MB as 10**6 bytes * Memory vendors define 1 MB as 2**20 bytes * Network equipment treats 1Mbit/s as 10**6 bits/s * Memory vendors define 1Mbit as 2**20 bits In practice, this means that a FLASH chip on a storage bus uses decimal prefixes, but that same flash chip on a memory bus uses binary prefixes. It would also be reasonable to assume that the contents of a 1Mbit FLASH chip would take 0.1s to transfer over a 10Mbit Ethernet link. That's however not the case due to different meanings of the prefix. The quantity 2MX is treated differently by gem5 depending on the unit X: * Physical quantities (s, Hz, V, A, J, K, C, F) use decimal prefixes. * Interconnect and NoC bandwidths (B/s) use binary prefixes. * Network bandwidths (bps) use decimal prefixes. * Memory sizes and storage sizes (B) use binary prefixes. Mitigate this ambiguity by consistently using the ISO/IEC/SI prefixes for binary multipliers for parameters and comments where appropriate. Change-Id: I797163c8690ae0092e00e371d75f5e7cebbcd1f5 Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/39579 Reviewed-by: Jason Lowe-Power <power.jg@gmail.com> Tested-by: kokoro <noreply+kokoro@google.com>
This is the gem5 simulator. The main website can be found at http://www.gem5.org A good starting point is http://www.gem5.org/about, and for more information about building the simulator and getting started please see http://www.gem5.org/documentation and http://www.gem5.org/documentation/learning_gem5/introduction. To build gem5, you will need the following software: g++ or clang, Python (gem5 links in the Python interpreter), SCons, SWIG, zlib, m4, and lastly protobuf if you want trace capture and playback support. Please see http://www.gem5.org/documentation/general_docs/building for more details concerning the minimum versions of the aforementioned tools. Once you have all dependencies resolved, type 'scons build/<ARCH>/gem5.opt' where ARCH is one of ARM, NULL, MIPS, POWER, SPARC, or X86. This will build an optimized version of the gem5 binary (gem5.opt) for the the specified architecture. See http://www.gem5.org/documentation/general_docs/building for more details and options. The basic source release includes these subdirectories: - configs: example simulation configuration scripts - ext: less-common external packages needed to build gem5 - src: source code of the gem5 simulator - system: source for some optional system software for simulated systems - tests: regression tests - util: useful utility programs and files To run full-system simulations, you will need compiled system firmware (console and PALcode for Alpha), kernel binaries and one or more disk images. If you have questions, please send mail to gem5-users@gem5.org Enjoy using gem5 and please share your modifications and extensions.