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[204.195.96.226]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-71e2ab0b7a1sm1170019b3a.197.2024.10.10.08.54.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Oct 2024 08:54:22 -0700 (PDT) Date: Thu, 10 Oct 2024 08:54:20 -0700 From: Stephen Hemminger <stephen@networkplumber.org> To: Mattias =?UTF-8?B?UsO2bm5ibG9t?= <mattias.ronnblom@ericsson.com> Cc: <dev@dpdk.org>, <hofors@lysator.liu.se>, Morten =?UTF-8?B?QnLDuHJ1cA==?= <mb@smartsharesystems.com>, Konstantin Ananyev <konstantin.v.ananyev@yandex.ru>, David Marchand <david.marchand@redhat.com>, Jerin Jacob <jerinj@marvell.com>, Luka Jankovic <luka.jankovic@ericsson.com>, Konstantin Ananyev <konstantin.ananyev@huawei.com>, Chengwen Feng <fengchengwen@huawei.com> Subject: Re: [PATCH v9 1/7] eal: add static per-lcore memory allocation facility Message-ID: <20241010085420.649d33c4@hermes.local> In-Reply-To: <20241010142205.813134-2-mattias.ronnblom@ericsson.com> References: <20241010141349.813088-2-mattias.ronnblom@ericsson.com> <20241010142205.813134-1-mattias.ronnblom@ericsson.com> <20241010142205.813134-2-mattias.ronnblom@ericsson.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions <dev.dpdk.org> List-Unsubscribe: <https://mails.dpdk.org/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://mails.dpdk.org/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <https://mails.dpdk.org/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> Errors-To: dev-bounces@dpdk.org On Thu, 10 Oct 2024 16:21:59 +0200 Mattias R=C3=B6nnblom <mattias.ronnblom@ericsson.com> wrote: > Introduce DPDK per-lcore id variables, or lcore variables for short. >=20 > An lcore variable has one value for every current and future lcore > id-equipped thread. >=20 > 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. >=20 > 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. >=20 > 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. >=20 > 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. >=20 > Signed-off-by: Mattias R=C3=B6nnblom <mattias.ronnblom@ericsson.com> > Acked-by: Morten Br=C3=B8rup <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