From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Pip Cet Newsgroups: gmane.emacs.bugs Subject: bug#46881: 28.0.50; pdumper dumping causes way too many syscalls Date: Fri, 5 Mar 2021 14:02:33 +0000 Message-ID: References: <83r1kw6b06.fsf@gnu.org> <90e99fc5-280d-63bb-9bc4-3efe89b9f9e2@dancol.org> <83a6riysnv.fsf@gnu.org> <83zgzixcfy.fsf@gnu.org> <83v9a5yfc0.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="32094"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 46881@debbugs.gnu.org, eggert@cs.ucla.edu To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Fri Mar 05 15:04:22 2021 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lIB41-0008Ea-Rz for geb-bug-gnu-emacs@m.gmane-mx.org; 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Fri, 05 Mar 2021 14:04:02 +0000 Original-Received: (at 46881) by debbugs.gnu.org; 5 Mar 2021 14:03:16 +0000 Original-Received: from localhost ([127.0.0.1]:33311 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lIB2y-0007xJ-EV for submit@debbugs.gnu.org; Fri, 05 Mar 2021 09:03:16 -0500 Original-Received: from mail-ot1-f50.google.com ([209.85.210.50]:40889) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lIB2x-0007x5-41 for 46881@debbugs.gnu.org; Fri, 05 Mar 2021 09:03:15 -0500 Original-Received: by mail-ot1-f50.google.com with SMTP id b8so1858097oti.7 for <46881@debbugs.gnu.org>; Fri, 05 Mar 2021 06:03:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=cWHWfVt8D63BMHYJ7E3DoVq79QE51UbB2DmOOJdPdk4=; b=EcB8NcerdTKF89sdzpDXoTaYfRwFVtXRRfoJ9r0iuxlybQIKKHC3hVOAX0rzHyadQi 1xZ7a0ze/zgIKqIB39s7TTMf0N2uGvlrwP3HlBEAgPppl8U3S3GbBnVZXfTIWStjjZVc XO/RUr3bReQFuVjevCPInXDrCFZ68yyu4ttfQG0MzX78InwuHf1tLDP4ekBfHAJ/P8jE +JQfA1vhm9vDolRB5UqGtazMS+oIzTNnO/ajCKTuAR56z07ZKKuEOk51Z7vIQAB2W6mZ rhSESwSQl6rPllK6ZcgcQFyK/apiMEwT3vZANzVgY24+IR/wf86z+b1DXS0weFzRjmLR LWAA== 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:cc; bh=cWHWfVt8D63BMHYJ7E3DoVq79QE51UbB2DmOOJdPdk4=; b=fDXaYRaLVy/+qGD0hS4DhXixrt2ceUpKYxV7y1hwP5wt75vY6GuNl0scw4UoRyHLW6 I3Qq6WxDITx/j48Fha9OCkREE1oF9bNyt/XoEs2qd1MMRVvuSnZCef0NfOco/8dwYtpR ozJC8b1ffD5eUzZsXnhRZwwIyWbiJnuW5h6Py1WzIYyH50bIPybmlQHFr9dmlq/NXLDo THsISsKuUPaU6FIEBleOokMl+12nFPD/se5mWPQejB9/1zsaO7/bcC4I3dShV/NbKoUf pQNjsoKsUMBtCn3Bs0RwCoWgoVq5JtBLH+WK6DRBc1gQ5Fpq8zyrAvh595s8uRVFD+l2 YU1g== X-Gm-Message-State: AOAM530/CTYwRm37wDW8rQXg+TGs/3DrDLLjJO77uelEyX0VUQSXrp02 6UH0e+AEz5KnZl3Fih2+bN+1E6N6PrWVfX+Y680= X-Google-Smtp-Source: ABdhPJzrAtMGz1K9b8uS5l7rcbwl5k/M8D+3xPeBXjvS0XvTRzIeWd0Sd9363g8dsnsYypGhOhsMbXKQiu0f+3AFkdk= X-Received: by 2002:a05:6830:11d4:: with SMTP id v20mr7987913otq.287.1614952989425; Fri, 05 Mar 2021 06:03:09 -0800 (PST) In-Reply-To: X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:201544 Archived-At: On Fri, Mar 5, 2021 at 1:16 PM Pip Cet wrote: > >I say let's go with stdio. > > Maybe setbuffer(3) could help us here? I could run some benchmarks for > that if the idea isn't out of the question. Actually, calling setbuffer() with a large buffer will make glibc reread the entire file on every fseek(), rendering the dump so slow I gave up and interrupted it. However, there's open_memstream: that would have the added advantage of actually making glibc write out the entire file in one go, so it seems to shave a few extra milliseconds off the build. (However however, glibc's memstreams are somewhat broken. I'll file a bug report if there isn't one already...) Still, that way we could use stdio today, leave the buffering to glibc, and hopefully be able to switch trivially to a "open this file but keep it in memory" combined memstream/FILE* one day. Pip