From mboxrd@z Thu Jan 1 00:00:00 1970 From: pak333@comcast.net Subject: xentrace buffering Date: Thu, 21 Jun 2007 20:58:38 +0000 Message-ID: <062120072058.2626.467AE67E0009D23000000A422207021633CCCCCC050E9F@comcast.net> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1196893365==" Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Mime-version: 1.0 Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org --===============1196893365== Content-Type: multipart/alternative; boundary="NextPart_Webmail_9m3u9jl4l_2626_1182459518_0" --NextPart_Webmail_9m3u9jl4l_2626_1182459518_0 Content-Type: text/plain Content-Transfer-Encoding: 8bit Hi, I am looking at the xentrace code and it looks like the individual cores/cpus write their (trace data) into individual regions of memory and they are all collected by xentrace and processed. I would like to have one trace buffer for all cores so that I can get an exact sequence in time order of the events that have occurred over the sampling period across cores/cpus. Is that easily doable>? If so, any pointers can someone send me pointers as to where I should start looking at modifying. Thanks -Prabha --NextPart_Webmail_9m3u9jl4l_2626_1182459518_0 Content-Type: text/html Content-Transfer-Encoding: 8bit

Hi,

I am looking at the xentrace code and it looks like the individual cores/cpus write their (trace data) into individual regions of memory and they are all collected by xentrace and processed.

I would like to have one trace buffer for all cores so that I can get an exact sequence in time order of the events that have occurred over the sampling period across cores/cpus.

Is that easily doable>? If so, any pointers can someone send me pointers as to where I should start looking at modifying.

Thanks

-Prabha

--NextPart_Webmail_9m3u9jl4l_2626_1182459518_0-- --===============1196893365== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel --===============1196893365==-- From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Gardner Subject: Re: xentrace buffering Date: Thu, 21 Jun 2007 17:00:55 -0600 Message-ID: <467B0327.1020001@hp.com> References: <062120072058.2626.467AE67E0009D23000000A422207021633CCCCCC050E9F@comcast.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <062120072058.2626.467AE67E0009D23000000A422207021633CCCCCC050E9F@comcast.net> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: pak333@comcast.net Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org pak333@comcast.net wrote: > Hi, > > I am looking at the xentrace code and it looks like the individual > cores/cpus write their (trace data) into individual regions of > memory and they are all collected by xentrace and processed. > > I would like to have one trace buffer for all cores so that I *can get > an exact sequence in time order* of the events that have occurred over > the sampling period across cores/cpus. > > Is that easily doable>? If so, any pointers can someone send me > pointers as to where I should start looking at modifying. > It's doable, but would require some work. I think the reason for having different buffers for each core is so that the trace code can be really light weight, since it doesn't have to deal with acquiring a write lock, etc. Theoretically, each core's clock should be very close to all the others, so the timestamp in the trace records should allow a reasonably accurate reconstruction of the order of events. Rob