From mboxrd@z Thu Jan 1 00:00:00 1970 From: Manuel Selva Subject: Re: Sample memory references with at least a given latency? Date: Thu, 05 Feb 2015 12:33:04 +0100 Message-ID: <54D354F0.2090405@gmail.com> References: <54D21524.8010305@bsc.es> <54D22AB8.4060607@bsc.es> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wi0-f181.google.com ([209.85.212.181]:64476 "EHLO mail-wi0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752436AbbBELdI (ORCPT ); Thu, 5 Feb 2015 06:33:08 -0500 Received: by mail-wi0-f181.google.com with SMTP id fb4so9875668wid.2 for ; Thu, 05 Feb 2015 03:33:06 -0800 (PST) In-Reply-To: <54D22AB8.4060607@bsc.es> Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Harald Servat Cc: "linux-perf-users@vger.kernel.org" Hi Harald, You are right, the perf mem tool dosn't support stting the latency threshold. It should be a very easy first contribution to kernel for myself ;-) Regarding the timestamp, I nver need such information, but as you said you can't tll to the hardware (on Intel I mean) to record it along with processor state information. I don't know how th kernel part of perf configure PEBS, but why would the kernel pay the overhead of an interrupt by using 1 slot buffers ? Only for recording timestamp ? ---- Manu On 02/04/2015 03:20 PM, Harald Servat wrote: > > Hello Manuel, > > I'm running Linux 3.11 but I don't see a way to setup the latency > threshold there. My option flags include: > > -t, --type= > -D, --dump-raw-samples= > -x, --field-separator > -C, --cpu-list > > so I guess that this option is not implemented in perf (at least on > 3.11). So I need to capture all the samples and then discard those that > surpass that threshold. > > Going back into your example, is it possible to capture / show the > timestamp for the captured samples? I've seen the Intel documentation, > and there aren't timestamps in PEBS entries so that may require > additional work. IIRC, someone of the list told me that perf allocates a > 1-entry PEBS buffer so every time PEBS fills it, perf somehow gets an > interrupt indicating that it has to flush it. This way, perf can > attribute a timestamp to that sample also. > > Thank you very much! > > > On 04/02/15 15:00, Manuel Selva wrote: >> Hi Harald, >> >> Yes you can with the "perf mem" tool. It has been introduced in kernel >> 3.10 (correct me if I am wrong, not very sure about that). It's built on >> top of perf mem record and perf mem report but hide for you the >> complxity of choosing the memory events . See "man perf mem" for th >> details. >> >> ---------- >> Manuel >> >> >> >> 2015-02-04 13:48 GMT+01:00 Harald Servat > >: >> >> Hello list, >> >> is there any way to configure perf to sample memory references >> through PEBS and enable the Load Latency Performance Monitoring >> Facility (section 18.7.1.2 from the Intel 64 and IA-32 Architectures >> Software Developer's Manual). >> >> Thank you very much in advance. >> >> WARNING / LEGAL TEXT: This message is intended only for the use of >> the >> individual or entity to which it is addressed and may contain >> information which is privileged, confidential, proprietary, or exempt >> from disclosure under applicable law. If you are not the intended >> recipient or the person responsible for delivering the message to the >> intended recipient, you are strictly prohibited from disclosing, >> distributing, copying, or in any way using this message. If you have >> received this communication in error, please notify the sender and >> destroy and delete any copies you may have received. >> >> http://www.bsc.es/disclaimer >> -- >> To unsubscribe from this list: send the line "unsubscribe >> linux-perf-users" in >> the body of a message to majordomo@vger.kernel.org >> >> More majordomo info at http://vger.kernel.org/__majordomo-info.html >> >> >> > > > WARNING / LEGAL TEXT: This message is intended only for the use of the > individual or entity to which it is addressed and may contain > information which is privileged, confidential, proprietary, or exempt > from disclosure under applicable law. If you are not the intended > recipient or the person responsible for delivering the message to the > intended recipient, you are strictly prohibited from disclosing, > distributing, copying, or in any way using this message. If you have > received this communication in error, please notify the sender and > destroy and delete any copies you may have received. > > http://www.bsc.es/disclaimer