From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16318 invoked by alias); 8 Jun 2006 14:31:30 -0000 Received: (qmail 16311 invoked by uid 22791); 8 Jun 2006 14:31:29 -0000 X-Spam-Status: No, hits=-1.4 required=5.0 tests=AWL,BAYES_20,UNPARSEABLE_RELAY X-Spam-Check-By: sourceware.org Received: from mail8.hitachi.co.jp (HELO mail8.hitachi.co.jp) (133.145.228.43) by sourceware.org (qpsmtpd/0.31) with ESMTP; Thu, 08 Jun 2006 14:31:25 +0000 Received: from mlsv4.hitachi.co.jp (unknown [133.145.228.16]) by mail8.hitachi.co.jp (Postfix) with ESMTP id 2399837C8A for ; Thu, 8 Jun 2006 23:31:23 +0900 (JST) Received: from MFILTER-S4.hitachi.co.jp by mlsv4.hitachi.co.jp (8.12.10/8.12.10) id k58EVMrA028972; Thu, 8 Jun 2006 23:31:23 +0900 Received: from vshuts1.hitachi.co.jp (unverified) by MFILTER-S4.hitachi.co.jp (Content Technologies SMTPRS 4.3.17) with SMTP id ; Thu, 8 Jun 2006 23:31:22 +0900 Received: from hsdlgw92.sdl.hitachi.co.jp ([133.144.7.20]) by vshuts1.hitachi.co.jp with SMTP id M2006060823312100373 ; Thu, 08 Jun 2006 23:31:22 +0900 Received: from vgate2.sdl.hitachi.co.jp by hsdlgw92.sdl.hitachi.co.jp (8.9.3/3.7W06060811) id XAA24209; Thu, 8 Jun 2006 23:31:19 +0900 Received: from maila.sdl.hitachi.co.jp ([133.144.14.196]) by vgate2.sdl.hitachi.co.jp (SAVSMTP 3.1.1.32) with SMTP id M2006060823311914588 ; Thu, 08 Jun 2006 23:31:19 +0900 Received: from [127.0.0.1] ([10.232.9.172]) by maila.sdl.hitachi.co.jp (8.13.1/3.7W04031011) with ESMTP id k58EVIvJ023242; Thu, 8 Jun 2006 23:31:19 +0900 Message-ID: <448834B6.1010002@sdl.hitachi.co.jp> Date: Thu, 08 Jun 2006 14:31:00 -0000 From: Masami Hiramatsu User-Agent: Thunderbird 1.5.0.2 (Windows/20060308) MIME-Version: 1.0 To: "bibo,mao" Cc: "Keshavamurthy, Anil S" , Ananth N Mavinakayanahalli , SystemTAP , Yumiko Sugita , Satoshi Oshima , Hideo Aoki , Prasanna S Panchamukhi , Jim Keniston Subject: Re: [PATCH]kprobe booster for IA64 References: <4485223C.8090109@sdl.hitachi.co.jp> <44868B03.70108@intel.com> In-Reply-To: <44868B03.70108@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2006-q2/txt/msg00579.txt.bz2 Hi bibo, bibo,mao wrote: > hiramatu san, > If the probed instruction can cause one fault, there may be some problem. > Because original instruction is copied into 2nd element of ainsn.insn, > instruction execution address is different, search_exception_tables result > will be different also. Thank you for your good advice. As far as I can see, the search_exception_tables() checks whether the page-fault address is expected to cause an exception. If it is correct, I think the problem can be avoided by disabling booster if the table contains the target address. For example; if (can_boost(template) && !search_exception_tables(p->addr)) { p->ainsn.inst_flag |= INST_FLAG_BOOSTABLE; } What would you think about this idea? Thanks > > Thanks > bibo,mao > > Masami Hiramatsu wrote: >> Hi, Anil and Ananth >> >> I ported the kprobe-booster to the IA64 architecture. >> This patch can be applied against 2.6.17-rc5-mm3. >> And here is the patch. Could you review it? >> >> This patch modifies kprobe as below; >> - Boost if the target bundle don't use B and X unit. >> - Introduce INST_FLAG_BOOSTABLE value for ainsn.insn_flag. >> If this flag is set, the kprobe is boostable. >> - Change instruction buffer(ainsn.insn) to an array of >> bundles which has three elements. The 2nd element and the >> 3rd element of this array are used for dynamic execution. >> >> And this patch is Lindent clean ;) >> >> I measured the overhead of the booster by using >> the benchmark kernel module attached to this mail. >> >> noprobe: 436 machine cycles >> noboost: 1162 machine cycles >> boosted: 829 machine cycles >> >> CPU spec: Itanium2 1.3GHz (2CPUs) >> >> >> -- Masami HIRAMATSU 2nd Research Dept. Hitachi, Ltd., Systems Development Laboratory E-mail: hiramatu@sdl.hitachi.co.jp