Re: [PATCH v9 1/7] eal: add static per-lcore memory allocation facility

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu, 10 Oct 2024 16:21:59 +0200
Mattias Rönnblom <mattias.ronnblom@ericsson.com> wrote:

> Introduce DPDK per-lcore id variables, or lcore variables for short.
> 
> An lcore variable has one value for every current and future lcore
> id-equipped thread.
> 
> The primary <rte_lcore_var.h> use case is for statically allocating
> small, frequently-accessed data structures, for which one instance
> should exist for each lcore.
> 
> Lcore variables are similar to thread-local storage (TLS, e.g., C11
> _Thread_local), but decoupling the values' life time with that of the
> threads.
> 
> Lcore variables are also similar in terms of functionality provided by
> FreeBSD kernel's DPCPU_*() family of macros and the associated
> build-time machinery. DPCPU uses linker scripts, which effectively
> prevents the reuse of its, otherwise seemingly viable, approach.
> 
> The currently-prevailing way to solve the same problem as lcore
> variables is to keep a module's per-lcore data as RTE_MAX_LCORE-sized
> array of cache-aligned, RTE_CACHE_GUARDed structs. The benefit of
> lcore variables over this approach is that data related to the same
> lcore now is close (spatially, in memory), rather than data used by
> the same module, which in turn avoid excessive use of padding,
> polluting caches with unused data.
> 
> Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
> Acked-by: Morten Brørup <mb@smartsharesystems.com>
> Acked-by: Konstantin Ananyev <konstantin.ananyev@huawei.com>
> Acked-by: Chengwen Feng <fengchengwen@huawei.com>
> Acked-by: Stephen Hemminger <stephen@networkplumber.org>

If you need to send v10, fix this please.



WARNING:TYPO_SPELLING: 'varibles' may be misspelled - perhaps 'variables'?
#336: FILE: doc/guides/prog_guide/env_abstraction_layer.rst:447:
+Lcore varibles are suitable for small object statically allocated at

WARNING:TYPO_SPELLING: 'identifer' may be misspelled - perhaps 'identifier'?
#867: FILE: lib/eal/include/rte_lcore_var.h:360:
+ * The pointer returned is only an opaque identifer of the variable. To