CircularQueue provides iterators which make it easier for users to
interact with it and helps abstract its internal state, but at the same
time it prevents standard algorithms like std::copy from recognizing
opportunities to use bulk copies to speed up execution. It also hides
the seams when wrapping around the buffer happens which std::copy
wouldn't know how to handle.
CircleBuf seems to be intended as a simpler type which doesn't hold
complex entries like the CircularQueue does, and instead just acts as a
wrap around buffer, like the name suggests. This change reimplements it
to not use CircularQueue, and to instead use an underlying vector.
The way internal indexing is handled CircularQueue was simplified
recently, and using the same scheme here means that this code is
actually not much more verbose than it was before. It also intrinsically
handles indexing and bulk accesses, and uses std::copy_n in a way that
lets it recognize and take advantage of contiguous storage and bulk
copies.
Change-Id: I78e7cfe174c52f60c95c81e5cd3d71c6052d4d41
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/38896
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Gabe Black <gabe.black@gmail.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This method lets you stretch the current chunk, if you want to skip over
some of the upcoming chunks since you've already handled their bytes.
For instance, if you were iterating over pages in a range of virtual
addresses, you might be able to handle multiple page sized chunks at
once if they were represented by a single large sized page table entry.
This mechanism would let you move past all the pages you had just
handled without having to walk through them all one by one.
Change-Id: I7d962f548947b77f0aa1b725036dbcc9e1b28659
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/38718
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This class had been trying to keep all indices within the modulus of the
queue size, and to use all elements in the underlying storage by making
the empty and full conditions alias, differentiated by a bool. To keep
track of the difference between a storage location on one trip around
the queue vs other times around, ie an alias once the indices had
wrapped, it also keep track of a "round" value in both the queue itself,
and any iterators it created.
All this bookkeeping significantly complicated the data structure.
Instead, this change modifies it to keep track of a monotonically
increasing index which is wrapped at the time it's used. Only the head
index and current size need to be tracked in the queue itself, and only
a pointer to the queue and an index need to be tracked in the iterators.
Theoretically, it's possible that this value could overflow eventually
since it increases forever, unlike before where the index wrapped and
was never larger than the queue's capacity. In practice, the type of the
index was changed from a uint32_t to a size_t, probably a 64 bit value
in modern systems, which will hold much larger values. Also, the round
counter and the index values together acted like a smaller than 64 bit
value anyway, since the round counter would overflow after 2^32 times
around a less than 2^32 entry queue.
One minor interface difference is that the head() and tail() values
returned by the queue are no longer pre-wrapped to be modulo the queue's
capacity. As long as consumers don't try to be overly clever and feed in
fixed values, do their own bounds checking, etc., something that would
be cumbersome considering the wrapping nature of the structure, this
shouldn't be an issue.
Also, since external consumers no longer need to worry about wrapping,
since only one of them was used in only one place, and because they
weren't even marked as part of the interface, the modulo helper
functions have been eliminated from the queue. If other code wants to
perform modulo arithmetic for some reason (which the queue no longer
requires) they can accomplish basically the same thing in basically the
same amount of code using normal math.
Also, rather than inherit from std::vector, this change makes the vector
internal to the queue. That prevents methods of the vector that aren't
aware of the circular nature of the structure from leaking out if
they're not overridden or otherwise proactively blocked.
On top of simplifying the implementation, this also makes it perform
*slightly* better. To measure that, I ran the following command:
$ time build/ARM/base/circular_queue.test.opt --gtest_repeat=100000 > /dev/null
and found a few percent improvement in total run time. While this
difference was small and not measured against realistic usage of the
data structure, it was still measurable, and at minimum doesn't seem to
have hurt performance.
Change-Id: Ic2baa28de135be7086fa94579bbec451d69b3b15
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/38478
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
If an `AddrRange` is not interleaved, return the input address in
`removeIntlvBits` and `addIntlvBits` to prevent undefined behavior. It
allows to use these methods in all cases without having to check
manually whether the range is interleaved.
Change-Id: Ic6ac8c4e52b09417bc41aa9380a24319c34e0b35
Signed-off-by: Isaac Sánchez Barrera <isaac.sanchez@bsc.es>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/37617
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
The methods `AddrRange::removeIntlvBits(Addr)` and
`AddrRange::addIntlvBits(Addr)` should be the inverse of one another,
but the latter did not insert the blanks for filling the removed bits in
the correct positions. Since the masks are ordered increasingly by the
position of the least significant bit of each mask, the lowest bit that
has to be inserted at each iteration is always `intlv_bit`, not needing
to be shifted to the left or right. The bits that need to be copied
from the input address are `intlv_bit-1..0` at each iteration.
The test `AddrRangeTest.AddRemoveInterleavBitsAcrossRange` has been
updated have masks below bit 12, making the old code not pass the test.
A new `AddrRangeTest.AddRemoveInterleavBitsAcrossContiguousRange` test
has been added to include a case in which the previous code fails. The
corrected code passes both tests.
This function is not used anywhere other than the tests and the class
`ChannelAddr`. However, it is needed to efficiently implement
interleaved caches in the classic mode.
Change-Id: I7d626a1f6ecf09a230fc18810d2dad2104d1a865
Signed-off-by: Isaac Sánchez Barrera <isaac.sanchez@bsc.es>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/37175
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
These were checking for gcc version 3, well below the minimum version we
support, and were hard wired to be enabled anyway. This change gets rid
of the check and the dead code on the hard wired off branch.
Also, this change cleans up the style in the surviving code and
simplifies it slightly.
Change-Id: I8df73a378f478413c111a4dea962450a37fb4092
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/35977
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The create() method on Params structs usually instantiate SimObjects
using a constructor which takes the Params struct as a parameter
somehow. There has been a lot of needless variation in how that was
done, making it annoying to pass Params down to base classes. Some of
the different forms were:
const Params &
Params &
Params *
const Params *
Params const*
This change goes through and fixes up every constructor and every
create() method to use the const Params & form. We use a reference
because the Params struct should never be null. We use const because
neither the create method nor the consuming object should modify the
record of the parameters as they came in from the config. That would
make consuming them not idempotent, and make it impossible to tell what
the actual simulation configuration was since it would change from any
user visible form (config script, config.ini, dot pdf output).
Change-Id: I77453cba52fdcfd5f4eec92dfb0bddb5a9945f31
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/35938
Reviewed-by: Gabe Black <gabeblack@google.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The stat system currently assumes that the decision to merge groups is
done at construction time. This makes it hard to implement global
statistics that live in a single global group.
This change adds some error checking to mergeStatGroup and marks it as
a public method.
Change-Id: I6a42f48545c5ccfcd0672bae66a5bc86bb042f13
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/35615
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Rather than just leaving some macros undefined if none of the scenarios
we checked for match, we should report an error so it's clear what
happened. Otherwise the places the macros are used will just not compile
properly, or worse will silently not work correctly.
Change-Id: Ie010d6b6d1b6a1496a45d9ebc0d75d1c804df12f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/35275
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This change replaces the __attribute__ syntax with the now standard [[]]
syntax. It also reorganizes compiler.hh so that all special macros have
some explanatory text saying what they do, and each attribute which has a
standard version can use that if available and what version of c++ it's
standard in is put in a comment.
Also, the requirements as far as where you put [[]] style attributes are
a little more strict than the old school __attribute__ style. The use of
the attribute macros was updated to fit these new, more strict
requirements.
Change-Id: Iace44306a534111f1c38b9856dc9e88cd9b49d2a
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/35219
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This macro probably would have been defined to "return" in some cases,
to be put after a call to a function that doesn't return so that the
compiler wouldn't think control would reach the end of a non-void
function. It was only ever defined to expand to nothing, and now that
[[noreturn]] is a standard attribute, it should never be needed going
forward.
Change-Id: I37625eab72deeaede77f9347116b9fddd75febf7
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/35217
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Sometimes ELF files have segments in them which are marked as loadable,
but which actually have zero size in memory. When setting up a memory
image we should drop those to avoid confusing other code which tries
to find the footprint of a memory image. No part of these segments,
including their starting address or ending address, need to actually
land on top of memory since they don't actually contain any data.
Change-Id: If8b61d10db139e0f688b6ceabcb8e6a898557469
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/35156
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Most DPRINTFs will be skipped over most of the time, and when they
aren't they'll already have overhead from string handling, output to the
console and/or a file, etc, which will drown out the behavior of a
branch.
Change-Id: I5475d7b5add63b44f60c0a1d46b4b14e6bf30fd3
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/34818
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
