This CL is part of a set of CLs that attempt to reduce how much work the
GC must do. See the design in https://go.dev/design/74299-runtime-freegc
This CL updates the smallNoScanStub stub in malloc_stubs.go to reuse
heap objects that have been freed by runtime.freegc calls, and generates
the corresponding size-specialized code in malloc_generated.go.
This CL only adds support in the specialized mallocs for noscan
heap objects (objects without pointers). A later CL handles objects
with pointers.
While we are here, we leave a couple of breadcrumbs in mkmalloc.go on
how to do the generation.
Updates #74299
Change-Id: I2657622601a27211554ee862fce057e101767a70
Reviewed-on: https://go-review.googlesource.com/c/go/+/715761
Reviewed-by: Junyang Shao <shaojunyang@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
This CL adds a generator function in runtime/_mkmalloc to generate
specialized mallocgc functions for sizes up throuht 512 bytes. (That's
the limit where it's possible to end up in the no header case when there
are scan bits, and where the benefits of the specialized functions
significantly diminish according to microbenchmarks). If the
specializedmalloc GOEXPERIMENT is turned on, mallocgc will call one of
these functions in the no header case.
malloc_generated.go is the generated file containing the specialized
malloc functions.
malloc_stubs.go contains the templates that will be stamped to create
the specialized malloc functions.
malloc_tables_generated contains the tables that mallocgc will use to
select the specialized function to call.
I've had to update the two stdlib_test.go files to account for the new
submodule mkmalloc is in. mprof_test accounts for the changes in the
stacks since different functions can be called in some cases.
I still need to investigate heapsampling.go.
Change-Id: Ia0f68dccdf1c6a200554ae88657cf4d686ace819
Reviewed-on: https://go-review.googlesource.com/c/go/+/665835
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Matloob <matloob@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
