Date: Mon, 13 Jan 2020 18:13:22 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: current@freebsd.org, arch@freebsd.org Subject: Fast sigblock Message-ID: <20200113161322.GD2068@kib.kiev.ua>
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https://reviews.freebsd.org/D12773 I intend to commit this in approximately week timeline. The overview of the feature is provided in the review summary above. Short story is, userspace can mask all maskable asynchronous signals with a single memory write, which allows to greatly speed up rtld for single-threaded processes. For small utilities like ls(1), the number of syscalls issued is cut by 1.5-2 times. I believe that a similar feature existed in Solaris, and I saw a mention of it added to DragonFlyBSD. This patch sit in my local repo for many years, I decided to commit it finally. See the following interesting comparision of the startup and runtime cost in term of syscalls https://drewdevault.com/2020/01/04/Slow.html Unpatched we are close to glibc, with the patch applied most of the syscalls issued are mmap(2)s from rtld private allocator and jemalloc(3).
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