https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88264
Bug ID: 88264
Summary: Support glibc-style tunables for <memory_resource>
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: redi at gcc dot gnu.org
Target Milestone: ---
"Tunables are a feature in the GNU C Library that allows application authors
and distribution maintainers to alter the runtime library behavior to match
their workload."
https://www.gnu.org/software/libc/manual/html_node/Tunables.html
We should support them in libstdc++ too. The resource types in
<memory_resource> are obvious candidates, but there might be others too
(default std::async launch policy?).
Possible tunables:
For monotonic_buffer_resource: the initial buffer size and growth factor.
For the pool resources: the supported pool sizes, if/when empty chunks are
released to the upstream resource, the default max_blocks_per_chunk and default
largest_required_pool_block, initial number of blocks per chunk (in
_M_alloc_pools).
For the pool resources it would also be possible to tune some of those numbers
per-resource by inventing an __extended_pool_options type that goes beyond the
two params that std::pmr::pool_options controls.
