From owner-freebsd-arch@freebsd.org Sun Nov 22 12:12:57 2015 Return-Path: Delivered-To: freebsd-arch@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C809FA32196 for ; Sun, 22 Nov 2015 12:12:57 +0000 (UTC) (envelope-from oliver.pinter@hardenedbsd.org) Received: from mail-wm0-x22c.google.com (mail-wm0-x22c.google.com [IPv6:2a00:1450:400c:c09::22c]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 5AD5A180F for ; Sun, 22 Nov 2015 12:12:57 +0000 (UTC) (envelope-from oliver.pinter@hardenedbsd.org) Received: by wmvv187 with SMTP id v187so126407267wmv.1 for ; Sun, 22 Nov 2015 04:12:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=hardenedbsd-org.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=xfcW7txb01iZxeBSPdDbLGZbjtEKSoSMwiKdeIu6dkE=; b=KPImeEYfVfqazGGWlvQaMer5UWp3sAz6RnPT59Ruj6hW/ufK5U38NDSXuwN74tYnB6 0R+SjeiAvFHY0bGYQw+B/DbkSwhbU+RdqMC5o9pQChQyQxY3ul/GCwWJpcuBS7p9OtcO om01uzz9FR3kHKM4ovEM61KMK6HSliuPLwcru3+uIh2zwUaFPkECDK6t1rST1lZkytjx VRK8vlI67wEFFZMBKuRsCnm3o83coHm5OYH6PN7dHslblAsKyF6BuzVGxD6FRpsXj7O3 z9bTlVFXgTpKds52yOyUQ9odBqCobZz/CUdy+XovoesJkQ9oibRYrYJfeOmiD3H1B1BL 0T9A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=xfcW7txb01iZxeBSPdDbLGZbjtEKSoSMwiKdeIu6dkE=; b=QfGIsP8nuelxyI/+ksusopdOj7M1p67x59pkJUV5agHGxlg1/2eTNzfRHrq/ExJm0w JjMTu2havr0Bf0wUZEJ6kqA9QQLF07yZUTS74VlbiKHWTwcIjsimZSUpo4PP4eTAhKjZ UdqDNxUu/tPP8De7C09Dj3MstVeG17cAgmX+VMMV88x0SKwLVw9p5tXQHP+Itosk16X9 FZviNVwIShy5RNouQqgd2VsWGgxpTG1Ka5hZq548sxzL0uipQcGrh3AX/xjsW6k91NBJ UDwU4CVXjWSEuvTfIXsGbpfYl4Rj3wXQOe7bt6oVTLxf1YM8kB4hgiAYaZFDSNkcX4K8 U2ZA== X-Gm-Message-State: ALoCoQnamqAMpM3TQhLIcwjr8Fj/uU5am8d0YjDNizfO6C5BBR7B7XjGktXco1oTe2DMA/OqyqBL MIME-Version: 1.0 X-Received: by 10.28.171.134 with SMTP id u128mr11009403wme.22.1448194374759; Sun, 22 Nov 2015 04:12:54 -0800 (PST) Received: by 10.194.243.6 with HTTP; Sun, 22 Nov 2015 04:12:54 -0800 (PST) In-Reply-To: <2753.1448173777@chaos> References: <20151122024542.GA44664@wkstn-mjohnston.west.isilon.com> <2753.1448173777@chaos> Date: Sun, 22 Nov 2015 13:12:54 +0100 Message-ID: Subject: Re: zero-cost SDT probes From: Oliver Pinter To: "Simon J. Gerraty" Cc: Mark Johnston , freebsd-arch@freebsd.org Content-Type: text/plain; charset=UTF-8 X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 22 Nov 2015 12:12:57 -0000 On 11/22/15, Simon J. Gerraty wrote: > Mark Johnston wrote: >> For the past while I've been experimenting with various ways to >> implement "zero-cost" SDT DTrace probes. Basically, at the moment an SDT >> probe site expands to this: > > Would it be feasible to compile the probes into the kernel > as active calls to a registrar function? > That would eliminate all the complexity of finding PC's > though you'd probably need to pass extra args to convey the point of the > probe? > > It would hurt boot time a little too - each probe point would make a > call to register itself (and get overwritten with nops as a reward) but > very simple? In opBSD I have already a similar mechanism for SMAP: https://github.com/opntr/opBSD/commits/op/gsoc2014/master . > _______________________________________________ > freebsd-arch@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-arch > To unsubscribe, send any mail to "freebsd-arch-unsubscribe@freebsd.org" >