From owner-freebsd-threads@FreeBSD.ORG Tue May 11 15:35:14 2004 Return-Path: Delivered-To: freebsd-threads@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 43F1816A4CF; Tue, 11 May 2004 15:35:14 -0700 (PDT) Received: from freefall.freebsd.org (freefall.freebsd.org [216.136.204.21]) by mx1.FreeBSD.org (Postfix) with ESMTP id DD00A43D3F; Tue, 11 May 2004 15:35:13 -0700 (PDT) (envelope-from davidxu@viatech.com.cn) Received: from viatech.com.cn (davidxu@localhost [127.0.0.1]) i4BMZASg022568; Tue, 11 May 2004 15:35:12 -0700 (PDT) (envelope-from davidxu@viatech.com.cn) Message-ID: <40A15602.9020902@viatech.com.cn> Date: Wed, 12 May 2004 06:38:58 +0800 From: David Xu User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.5) Gecko/20031206 Thunderbird/0.3 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Daniel Eischen References: In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit cc: threads@freebsd.org cc: Bruce Evans cc: John Baldwin Subject: Re: Threads and userland profliing... X-BeenThere: freebsd-threads@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Threading on FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 11 May 2004 22:35:14 -0000 Daniel Eischen wrote: >On Tue, 11 May 2004, John Baldwin wrote: > > > >>Currently in the pstats structure we have a uprof substructure that holds >>various values used for userland processing. Does anyone know what parts of >>that structure are supposed to be per-process and which are supposed to be >>per-thread? pr_addr and pr_ticks seem to be definite per-thread items, but >>the other values I'm not sure of. >> >>Specifically, is the userland table that pr_base, pr_size, pr_off, and >>pr_scale refer to per-thread or is it supposed to be shared among all threads >>in a process? If it's shared, do we need to be using casuptr() or something >>similar in addupc_intr() instead of a separate fetch and store? >>addupc_task() also has a race window between the copyin() and copyout() as >>well if it is shared. If its private, then I suppose each thread has to call >>profil(2) and gprof is supposed to be smart enough to make that happen? Does >>POSIX have anything to say regarding threads and profil(2)? >> >> > >POSIX does not define profil(2). Here's what Solaris 9 has to >say about it: > > In Solaris releases prior to 2.6, calling profil() in a mul- > tithreaded program would impact only the calling LWP; the > profile state was not inherited at LWP creation time. To > profile a multithreaded program with a global profile > buffer, each thread needed to issue a call to profil() at > threads start-up time, and each thread had to be a bound > thread. This was cumbersome and did not easily support > dynamically turning profiling on and off. In Solaris 2.6, > the profil() system call for multithreaded processes has > global impact - that is, a call to profil() impacts all > LWPs/threads in the process. This may cause applications > that depend on the previous per-LWP semantic to break, but > it is expected to improve multithreaded programs that wish > to turn profiling on and off dynamically at runtime. > >We should probably avoid the mistake that Solaris < 2.6 >made. > > > Because I never thought the profile buffer should be per-process, did you mean that it should be per-process too? David Xu