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2017-11-29cpu-minor: Add missing instruction statsDavid Guillen Fandos
Change-Id: I811b552989caf3601ac65a128dbee6b7bb405d7f Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> [ Updated to use IsVector instruction flag. ] Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/5732 Reviewed-by: Gabe Black <gabeblack@google.com>
2016-11-09style: [patch 1/22] use /r/3648/ to reorganize includesBrandon Potter
2016-12-21cpu: disallow speculative update of branch predictor tables (o3)Arthur Perais
The Minor and o3 cpu models share the branch prediction code. Minor relies on the BPredUnit::squash() function to update the branch predictor tables on a branch mispre- diction. This is fine because Minor executes in-order, so the update is on the correct path. However, this causes the branch predictor to be updated on out-of-order branch mispredictions when using the o3 model, which should not be the case. This patch guards against speculative update of the branch prediction tables. On a branch misprediction, BPredUnit::squash() calls BpredUnit::update(..., squashed = true). The underlying branch predictor tests against the value of squashed. If it is true, it restores any speculatively updated internal state it might have (e.g., global/local branch history), then returns. If false, it updates its prediction tables. Previously, exist- ing predictors did not test against the "squashed" parameter. To accomodate for this change, the Minor model must now call BPredUnit::squash() then BPredUnit::update(..., squashed = false) on branch mispredictions. Before, calling BpredUnit::squash() performed the prediction tables update. The effect is a slight MPKI improvement when using the o3 model. A further patch should perform the same modifications for the indirect target predictor and BTB (less critical). Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
2016-07-21cpu: Fix Minor SMT WFI/drain interaction issuesMitch Hayenga
The behavior of WFI is to cause minor to cease evaluating pipeline logic until an interrupt is observed, however a user may wish to drain the system while a core is sleeping due to a WFI. This patch makes WFI drain. If an actual drain occurs during a WFI, the CPU is already drained and will immediately be ready for swapping, checkpointing, etc. This should not negatively impact performance as WFI instructions are 'stream-changing' (treated like unpredicted branches), so all remaining instructions are wrong-path and will be squashed rapidly. Change-Id: I63833d5acb53d8dde78f9f0c9611de0ece385e45
2016-07-21cpu: Add SMT support to MinorCPUMitch Hayenga
This patch adds SMT support to the MinorCPU. Currently RoundRobin or Random thread scheduling are supported. Change-Id: I91faf39ff881af5918cca05051829fc6261f20e3
2014-11-14arm: Fixes based on UBSan and static analysisAndreas Hansson
Another churn to clean up undefined behaviour, mostly ARM, but some parts also touching the generic part of the code base. Most of the fixes are simply ensuring that proper intialisation. One of the more subtle changes is the return type of the sign-extension, which is changed to uint64_t. This is to avoid shifting negative values (undefined behaviour) in the ISA code.
2014-07-23cpu: `Minor' in-order CPU modelAndrew Bardsley
This patch contains a new CPU model named `Minor'. Minor models a four stage in-order execution pipeline (fetch lines, decompose into macroops, decompose macroops into microops, execute). The model was developed to support the ARM ISA but should be fixable to support all the remaining gem5 ISAs. It currently also works for Alpha, and regressions are included for ARM and Alpha (including Linux boot). Documentation for the model can be found in src/doc/inside-minor.doxygen and its internal operations can be visualised using the Minorview tool utils/minorview.py. Minor was designed to be fairly simple and not to engage in a lot of instruction annotation. As such, it currently has very few gathered stats and may lack other gem5 features. Minor is faster than the o3 model. Sample results: Benchmark | Stat host_seconds (s) ---------------+--------v--------v-------- (on ARM, opt) | simple | o3 | minor | timing | timing | timing ---------------+--------+--------+-------- 10.linux-boot | 169 | 1883 | 1075 10.mcf | 117 | 967 | 491 20.parser | 668 | 6315 | 3146 30.eon | 542 | 3413 | 2414 40.perlbmk | 2339 | 20905 | 11532 50.vortex | 122 | 1094 | 588 60.bzip2 | 2045 | 18061 | 9662 70.twolf | 207 | 2736 | 1036