Commit graph

2 commits

Author SHA1 Message Date
Andrew Bardsley
1a45a8c5d3 cpu: Fix memory access in Minor not setting parent Request flags
This patch fixes cases where uncacheable/memory type flags are not set
correctly on a memory op which is split in the LSQ.  Without this
patch, request->request if freely used to check flags where the flags
should actually come from the accumulation of request fragment flags.

This patch also fixes a bug where an uncacheable access which passes
through tryToSendRequest more than once can increment
LSQ::numAccessesInMemorySystem more than once.
2014-09-12 10:22:49 -04:00
Andrew Bardsley
0e8a90f06b cpu: `Minor' in-order CPU model
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
2014-07-23 16:09:04 -05:00