From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 73622 invoked by alias); 1 Dec 2016 18:47:13 -0000 Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org Received: (qmail 73612 invoked by uid 89); 1 Dec 2016 18:47:12 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.2 spammy=HTo:U*jistone, Aubrey, aubrey, 20879 X-HELO: mail-vk0-f51.google.com Received: from mail-vk0-f51.google.com (HELO mail-vk0-f51.google.com) (209.85.213.51) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 01 Dec 2016 18:47:02 +0000 Received: by mail-vk0-f51.google.com with SMTP id x186so133535652vkd.1 for ; Thu, 01 Dec 2016 10:47:02 -0800 (PST) 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:from:date :message-id:subject:to:cc; bh=dme6rDee+d0Zyp1hHYCqpyY8WQcbc5N1njVXLSirnmY=; b=B2WP2Ac+blV7BSuLogijIELeCnipb9A7bN883mwA7MkLhxnCsLWiSx3w2tCLz6Hxdu 7m9dDz3h61bw35Fz7cffeUQ6r8kHMqtI/irH0pYEJt4d7WUu4zwXBVNYV96ejhk0Cv+i 5F/nEI8oUpyImDwyJhSKYGExfsmSPkiPDDG5awqOO+ohPHEMQkVVDp9BC4rBFv6zsphl SZ3fhz55itSH9JuFKI7YdFERVKuulYKXQ1XhdsNFY+h7KAPffzF0aycqEAM3ct3ZYl2k VI43GtEfqGv4UJa3k8c6oIUsZRnIl0OOkg3TN+i8rF5tT6EbenQ7BTfW0IwfpmrGOspe NaDg== X-Gm-Message-State: AKaTC00+1+Yh4TQftpNkePLttjS+dcOL5NbIXYBCuNgvfUH1RZFA5TV4eDl6Q3LpVLFKDNFKtABBNlHR0IkCaA8z X-Received: by 10.31.228.71 with SMTP id b68mr14885087vkh.163.1480618020653; Thu, 01 Dec 2016 10:47:00 -0800 (PST) MIME-Version: 1.0 Received: by 10.103.85.23 with HTTP; Thu, 1 Dec 2016 10:47:00 -0800 (PST) In-Reply-To: References: From: Cody Santing Date: Thu, 01 Dec 2016 18:47:00 -0000 Message-ID: Subject: Re: kernel function probe overhead To: Aubrey Li , "Frank Ch. Eigler" , Josh Stone Cc: systemtap@sourceware.org Content-Type: text/plain; charset=UTF-8 X-IsSubscribed: yes X-SW-Source: 2016-q4/txt/msg00106.txt.bz2 Hello Aubrey, >> Ah, I note that we don't track occurrences of lock contention, >> even though we could. Opened https://sourceware.org/bugzilla/show_bug.cgi?id=20879 > > okay, thanks, I'll keep an eye on this ticket. > I have yet to update the ticket but I have added tracking of lock contention. The number of lock contention occurrences on global variables will be printed following the probe hit report from the '-t' option. >> That inconsistency dramatic contention or caching or some other source >> of jitter. Having the variance figure in there would be useful though. >> Would anyone like to give that a try? (translate.cxx line 2283ish and >> runtime/linux/common_session_state.h _stp_stat_init area). >> I have also added variance to the '-t' option. It is immediately following min/avg/max of each probe. > > If there is a patch delivered against git head, I can apply it and > paste the output here. > You should find the patch there. Give it a shot, if you have any feedback I would like to hear it. Thank you, Cody Santing