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Beginner
55 Views

Hotspots questions in VTune 7.2

Iam using licensed version of Vtune Performance Analyzer 7.2. I have a question regarding Vtune:

I want to analyze the cause of Hotspots in my source code, but when I am clicking on "Get advice using Intel Tuning Assistant" option (in disassembly mode), for any line/portion of code, it is just displaying message "No assembly level tuning advice available".

While at the training session of Vtune it is showing some useful advice specifying the real cause of more clockticks for hotspots on doing same.

I also tried it for "Mixed by combination/source/execution"options. On selecting option of "Mixed by combination" it showed tuning assistant displaying "workload insights-only clockticks and processor time" and "system info-CPU configuration".

Is there any setting/option for getting really helpful tuning advices so that I can fix my Hotspots.

Please reply as soon as possible.

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5 Replies
Vladimir_T_Intel
Moderator
55 Views

Please, try getting tuning advice "For Current Function" in the assembly view of switch to the source view. The assembly level is often not enough to collect all information regarding performance problems for Tuning Assistant. Actually, the best level for getting tuning advice is Hotspot.

And besides, since you are using quiteold version of VTune,there could be the case when you have a microprocessor which is not recognized/supportedby TA to compile a meaningful advice.

khalirohit
Beginner
55 Views

Hi Vladimir,

Thanx for response, but my points are:

1. I had already tried to get Tuning Advice by using allavailable optionsof "Mixed by combination/source/execution as well as disassembly only"options,as I have mentioned in my question earlier.

2.My system Configration is

CPU Architecture: IA32(Family 15; Model 4; Stepping 9)

CPU Speed(MHz):2666

So I don't thinkI am using a microprocessor which is not recognized/supportedby TA to compile a meaningful advice.

3.Obviously I am trying to get Tuning advice for Hotspots only smiley [:-)]

So please tell me, is there any setting/option for getting really helpful tuning advices so that I can fix my Hotspots?

Regards

Rohit Khali

Vladimir_T_Intel
Moderator
55 Views

Hi Rohit,

Let me try to answer to the questions as they appear in the enumeration:

1. Actually I meant to get tuning advice using "For Current Function" option in the context menu. Its more useful in any view (source, assembly, mixed). Sorry, if I was not clear. But if you switch to the Hotspot view and request tuning advice over a hotspot function, I believe youll get more meaningful advice.

2. Yes, agree. Your CPU is P4.

3. Of course you are :). But the resulting advice depends on from which level you requested it, and as I mentioned in (1), the best level is Hotspot view. The downside is that the advice will be more common rather then specific for particular instructions. If you want advice against a particular asm instruction, see the penalty column. In case there are no warnings there, the hot instruction should be considered in the context of whole loop or function this asm instruction belongs to. And finally, for more complete tuning advice switch on the option Automatically generate tuning advice->Max: when creating sampling configuration with Wizard.

khalirohit
Beginner
55 Views

Hi Vladimir,

Thanks for Responding.

While trying to get Tuning advices I tried all options as you mentioned in your reply, but again I got same thing as I was getting previously, means Tuning assistant is showing Workload/Module/Hotspots Insights and System Info mentioning all my functions Prototypes with clockticks and System information, but in Tuning Advice section a message More Measurements Should Be Taken to Determine Exactly What Steps Should Be Taken to Improve Perform... is there for all functions of my Application .

Although my Application contains a number of functions, I also launched it for much longer time on Vtune but it didnt help, however it should not be the case with Vtune as it should be independent of size-time taken by application.

I am using Sampling Configuration Wizard, Automatically generate Tuning advice, Many sampling runs with more advices, Event based using processor counter, when the application terminates options.

I think problem in my case is a column Event Groups to collect for tuning assistance where a message is being displayed <no valid event groups for tuning assistance> I am not able to edit or put any event in this column.

Meanwhile I just surfed at a link http://software.intel.com/en-us/articles/optimizing-for-intel-pentiumr-m-processor-with-intel-vtunet... displaying two events in the same column.

One more things the link is showing both options Event based using processor counter and after duration of checked together, while in my case I can never check both options together, though I am doing same thing, why is it so?

So now

1. Is it the reason for my problem? As I dont think I am doing anything wrong at options like Context menu, Hotspot view

after Vtune Processing is completed.

2. Or is it because of Hardware (System configuration) and Software (OS-Windows XP Professional), which I am using?

(ButVtune 7.2 release notes mentions thatVtune supports IA 32 and WINXP Profess ional both)

Please try to resolve this problem now as it has become a mystery for meSad smiley [:(] and I want to solve it desperately.

Hope you understood the problem well and sorry for using too complex language, as it is not easy for me to describe problem as it is in simple words smiley [:-)]

Regards

Rohit Khali

Vladimir_T_Intel
Moderator
55 Views

Hi Rohit,

According to what you described, there is nothing wrong among what you were doing. So, it sounds like a bug for me. Why not you try the latest version of VTune? At least you can be sure that your application is not making VTune be stuck in generating advice.

You can download the evaluation version here and try it with your application.