Newsgroups: php.internals Path: news.php.net Xref: news.php.net php.internals:111311 Return-Path: Delivered-To: mailing list internals@lists.php.net Received: (qmail 48747 invoked from network); 4 Aug 2020 09:14:13 -0000 Received: from unknown (HELO php-smtp4.php.net) (45.112.84.5) by pb1.pair.com with SMTP; 4 Aug 2020 09:14:13 -0000 Received: from php-smtp4.php.net (localhost [127.0.0.1]) by php-smtp4.php.net (Postfix) with ESMTP id 6FF9118050B for ; Tue, 4 Aug 2020 01:11:50 -0700 (PDT) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on php-smtp4.php.net X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HTML_MESSAGE,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2, SPF_HELO_NONE,SPF_NONE autolearn=no autolearn_force=no version=3.4.2 X-Spam-Virus: No X-Envelope-From: Received: from mail-wr1-f42.google.com (mail-wr1-f42.google.com [209.85.221.42]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by php-smtp4.php.net (Postfix) with ESMTPS for ; Tue, 4 Aug 2020 01:11:49 -0700 (PDT) Received: by mail-wr1-f42.google.com with SMTP id a14so36523812wra.5 for ; Tue, 04 Aug 2020 01:11:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=beberlei-de.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=sBIzxNvWleTK8OohNdOr7J+wuSzcw2NfOEcvRTOjcPo=; b=Uyq/yLsPfQSMlfAi6GgiEsrPY5FIh6WR1tJCl+ZEiMeikXCsxuVP3SkUKkacgjjccl g9N/cJk7XRk5wOD2tgw1WD8DUBsXzRqLJkmq4O9lRCXqu0lhVLpjMH0JVKNKiu2ZpW8D D2Or+MHEJAV2egtQcx4MIg3xcSpDtz4QPlysYcgmbRnbIpCwhlVyJ/PSgy5iTZ9pf/sn xtwTli6B3xeyQTa1tCyTz8r+uHF1uCzXPvz2mGcJkL7vgW4xCXWpJKI8tVb2WH2CQrzi N7uP96t4UdkpmnyJThDKLzG652kDz/H8LqzNpI740/Xo3IQkb/uDzUZvc/UvWA2aeDhg l8Qg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=sBIzxNvWleTK8OohNdOr7J+wuSzcw2NfOEcvRTOjcPo=; b=HW6jlCDWB8nN2gK0szFFGShbneYbOPEB04kA7OehTQtMs3bNZCAiX7piz5sdaZQQOX bx/v/PuKspktf5nd8Q5fPuCtRmc5MZMu6/YIOho+Lc4JA/GRYmN8dA85GmYJxoWVawqx /im/t4fKOf9oK43s9Ws2aG11hzkTK3OHYSOwmuz/mbjh+0kpS8AZcWJ1DZMxGoGHI2jl G1DcYV66Z+uFFCkQApJIV7vhqeT3tJ8kEVhDGz5WFlrRW+jU2IvpO2GfXRty+Lxkg29E ksOeI7wJyEiCYKOdjktaz568WTrhbIm85tMtrXISi0u0WpujEEl6rXpCpEi6R/MQ+Sam DHTQ== X-Gm-Message-State: AOAM533bJTV2SOX1l2cfvwHHvtMoK/gh3nBlseV7z9napPomzOQsx0JA Sh1tVq81vFcCtmu2LfZ48W8GsV+nZnfhziqhk925VlswqX9YFg== X-Google-Smtp-Source: ABdhPJx4OKMnW1dJ7ny0V1kk5v7ybNYwqWbqzSlJY95ly4AloJNYz1jmpUz/h+5EbUI3OYgLEm5PaEC8c1EVsyTr6UA= X-Received: by 2002:adf:dcc8:: with SMTP id x8mr19516600wrm.16.1596528706834; Tue, 04 Aug 2020 01:11:46 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: Date: Tue, 4 Aug 2020 10:11:35 +0200 Message-ID: To: PHP Internals , Dmitry Stogov , Nikita Popov Content-Type: multipart/alternative; boundary="00000000000072024505ac08ce21" Subject: Re: @@Jit Attribute Considerations From: kontakt@beberlei.de (Benjamin Eberlei) --00000000000072024505ac08ce21 Content-Type: text/plain; charset="UTF-8" On Mon, Aug 3, 2020 at 7:44 PM Benjamin Eberlei wrote: > Hi, > > I am going to pick up a discussion from > https://github.com/php/php-src/pull/5915 about the @@Jit attribute. > > Nikita mentioned he is still not 100% clear what the usecase is for @@Jit > attribute and asked to discuss here. > > The reason is that the default tracing JIT is clever to decide itself when > to JIT or not, better not interfere with that. In case you run the tracing > JIT, only @@Jit("off") has an effect the others @@Jit("tracing") and > @@Jit("function") get ignored. > > Only the trigger mode 4 (attributes) is actually using @@Jit("tracing") > and "function". This trigger mode feels like micro-management for > developers and since it has virtually no spotlight in discussions and blog > posts about the JIT at the moment, we don't know if it brings benefits. > > Maybe for now it would be better to remove docblock / attribute support > for the JIT, and take a new attempt at it in 8.1? That prevents us from > rolling something we regret having to maintain later. > I updated the PR https://github.com/php/php-src/pull/5915 with the following things: - Removed attribute trigger mode for now. - Removed obsolete doc comment trigger mode - Add @@Jit("off") to disable JIT for an op_array or script Open questions: - Are we ok with removing @Jit("on"), @@Jit("tracing") and @@Jit("function") for now to thoroughly discuss best approach for 8.1? - Rename @@Jit to something more specific like @@JitOptions or @@JitHint? - Remove the attribute trigger constant 4, and move tracing JIT to use 4 instead of 5? Outlook: We need to think about what the @@Jit attribute should actually mean in context of the function or tracing JIT. Personally it probably means "Always Jit this function regardless of hot counter or tracing results". I believe we don't need the attributes trigger mode, as everything happens either in context of function or tracing JIT. > greetings > Benjamin > --00000000000072024505ac08ce21--