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([2804:1b3:a7c2:94e:bdbe:c355:6ac:193b]) by smtp.gmail.com with ESMTPSA id 19-20020a170902c11300b001bc6e6069a6sm7933070pli.122.2023.11.22.06.05.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 22 Nov 2023 06:05:33 -0800 (PST) Message-ID: <273564f9-9348-44c0-b8ce-90a459beadff@linaro.org> Date: Wed, 22 Nov 2023 11:05:31 -0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: reducing the contention in dl_iterate_phdr (reloaded) Content-Language: en-US To: Vincenzo Innocente , "libc-help@sourceware.org" References: From: Adhemerval Zanella Netto Organization: Linaro In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-5.2 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,KAM_SHORT,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On 22/11/23 08:13, Vincenzo Innocente via Libc-help wrote: > I found this old thread about lack of concurrency in dl_iterate_phdr that affects gcc unwinding. > https://sourceware.org/pipermail/libc-help/2020-May/005275.html > > I discover this issue while experimenting with C++23 std::stacktrace in a multithread application. > > Has been made any progress on the subject since May 2020? Starting with version 2.35, glibc provides _dl_find_object [1] which is used by libgcc unwinder [2] functions to fix the scalability issues. The libstdc++ must be built against a glibc 2.35 headers to enable it. [1] https://gcc.gnu.org/pipermail/gcc-patches/2021-December/586170.html [2] https://www.mail-archive.com/gcc-patches@gcc.gnu.org/msg273082.html