When cpu_no_init.go was created most architectures did not have
code in the doinit function. Currently only mips(le), riscv64 and
wasm do not have empty doinit functions.
Keeping cpu_no_init.go around does not reduce the work to satisfy
the build process when adding support for new architectures.
To support a new architecture a new file or build directive has to
be added to an existing file at any rate to define the constant
CacheLinePadSize. A new empty doinit can then be created in the
new file or the existing doinit can be reused when adding the
additional build directive.
Change-Id: I58a97f8cdf1cf1be85c37f4550c40750358aa031
Reviewed-on: https://go-review.googlesource.com/c/go/+/263801
Trust: Martin Möhrmann <moehrmann@google.com>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
The new constant CacheLinePadSize can be used to compute best effort
alignment of structs to cache lines.
e.g. the runtime can use this in the locktab definition:
var locktab [57]struct {
l spinlock
pad [cpu.CacheLinePadSize - unsafe.Sizeof(spinlock{})]byte
}
Change-Id: I86f6fbfc5ee7436f742776a7d4a99a1d54ffccc8
Reviewed-on: https://go-review.googlesource.com/131237
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Implements detection of x86 cpu features that
are used in the go standard library.
Changes all standard library packages to use the new cpu package
instead of using runtime internal variables to check x86 cpu features.
Updates: #15403
Change-Id: I2999a10cb4d9ec4863ffbed72f4e021a1dbc4bb9
Reviewed-on: https://go-review.googlesource.com/41476
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
