From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2A235C433DF for ; Mon, 6 Jul 2020 10:53:54 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E640620715 for ; Mon, 6 Jul 2020 10:53:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=xen.org header.i=@xen.org header.b="YoG4SA6Q" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E640620715 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jsOkQ-0006zk-Cj; Mon, 06 Jul 2020 10:53:18 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jsOkP-0006zf-Bd for xen-devel@lists.xenproject.org; Mon, 06 Jul 2020 10:53:17 +0000 X-Inumbo-ID: e552e786-bf76-11ea-8c61-12813bfff9fa Received: from mail.xenproject.org (unknown [104.130.215.37]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id e552e786-bf76-11ea-8c61-12813bfff9fa; Mon, 06 Jul 2020 10:53:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=ASS/EyAWJ4zMVNhcFNnYTPSeGf5qD5vkk3McVKOf1nY=; b=YoG4SA6QLxbC9Vy79cxbjqRVvl vbLzRL1xrBhHxIROM8qXGSkWmQoXVcpbQWyR6bFB8qStg2JsvFGyJFG+JyuHzFMN7qCwmX9x4qaap CJ5FRAg1mfz8nNIZrv4FIbtfIGJWSmLMbO1DKQmnJThZ7U72QZ2taTnHKw4y6A78GB7o=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jsOkK-0004A1-KH; Mon, 06 Jul 2020 10:53:12 +0000 Received: from 54-240-197-232.amazon.com ([54.240.197.232] helo=a483e7b01a66.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1jsOkK-0003Gy-Aj; Mon, 06 Jul 2020 10:53:12 +0000 Subject: Re: [PATCH v5 05/11] tools/libxl: add vmtrace_pt_size parameter To: =?UTF-8?Q?Micha=c5=82_Leszczy=c5=84ski?= , xen-devel@lists.xenproject.org References: <1763045628.19744689.1593975740414.JavaMail.zimbra@cert.pl> From: Julien Grall Message-ID: Date: Mon, 6 Jul 2020 11:53:09 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <1763045628.19744689.1593975740414.JavaMail.zimbra@cert.pl> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 8bit X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: luwei kang , Wei Liu , Andrew Cooper , Ian Jackson , George Dunlap , Anthony PERARD , tamas lengyel , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Hi, On 05/07/2020 20:02, Michał Leszczyński wrote: > ----- 5 lip 2020 o 20:54, Michał Leszczyński michal.leszczynski@cert.pl napisał(a): > >> From: Michal Leszczynski >> >> Allow to specify the size of per-vCPU trace buffer upon >> domain creation. This is zero by default (meaning: not enabled). >> >> Signed-off-by: Michal Leszczynski >> --- >> docs/man/xl.cfg.5.pod.in | 11 +++++++++++ >> tools/golang/xenlight/helpers.gen.go | 2 ++ >> tools/golang/xenlight/types.gen.go | 1 + >> tools/libxl/libxl.h | 8 ++++++++ >> tools/libxl/libxl_create.c | 1 + >> tools/libxl/libxl_types.idl | 2 ++ >> tools/xl/xl_parse.c | 22 ++++++++++++++++++++++ >> 7 files changed, 47 insertions(+) >> >> diff --git a/docs/man/xl.cfg.5.pod.in b/docs/man/xl.cfg.5.pod.in >> index 0532739c1f..670759f6bd 100644 >> --- a/docs/man/xl.cfg.5.pod.in >> +++ b/docs/man/xl.cfg.5.pod.in >> @@ -278,6 +278,17 @@ memory=8096 will report significantly less memory available >> for use >> than a system with maxmem=8096 memory=8096 due to the memory overhead >> of having to track the unused pages. >> >> +=item B >> + >> +Specifies the size of processor trace buffer that would be allocated >> +for each vCPU belonging to this domain. Disabled (i.e. >> +B by default. This must be set to >> +non-zero value in order to be able to use processor tracing features >> +with this domain. >> + >> +B: The size value must be between 4 kB and 4 GB and it must >> +be also a power of 2. This seems to suggest that 4 kB is allowed. But looking at the code below, you are forbidding the value. [...] > As there were many different ideas about how the naming scheme should be > and what kinds of values should be passed where, I would like to discuss > this particular topic. Right now we have it pretty confusing: > > * user sets "processor_trace_buffer_size" option in xl.cfg > * domain creation hypercall uses "vmtrace_pt_order" (derived from above) You don't only use the order in the hypercall but also the public interface of libxl. > * hypervisor side stores "vmtrace_pt_size" (converted back to bytes) My preference would be to use the size everywhere, but if one still prefer to use the order in the hypercall then the libxl interface should use the size. See my comment in v4 for the rationale. Cheers, -- Julien Grall