Tuesday, July 27, 2010

Load runner Vs Silk performer

Can anyone speak about the relative merits of these two tools? I am new to LoadRunner, but my company is merging with another that uses Segue's tools.

I know of one difference, i.e. that LoadRunner allows recording against UNIX and Windows RTE clients.

Thanks for any advice;

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unregistered posted 07-22-1999 10:06 PM Edit/Delete Message Copy This Message Reply w/Quote Search for more posts by PerformerUser SilkPerformer can also record traffic from a Unix/Mac machine. Since the web recorder is proxy based, it doesn't matter what kind of machine the client is running on.

As for relative merits, after a serious comparison of the products, we found that SilkPerformer actually simulates browsers correctly. It allows simulation of multiple connections correctly and the modem simulation actually works. The script is also much smaller in size and the tool scales very well with a large number of simulated users. You can simulate multiple protocols in a single script (HTTP, POP3, FTP, SMTP, LDAP, IIOP, TCP/IP, etc.) so you don't have to create different scripts for different protocols. The scripting language has a whole lot of specialized functions optimized for load testing. And finally, it doesn't crash frequently, which is a good thing in a qualaity assurance tool! Bottom line is: SilkPerformer is a much more serious tool. Hope that helps.

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unregistered posted 08-06-1999 08:01 AM Edit/Delete Message Copy This Message Reply w/Quote Search for more posts by AdamA We have found through thorough evaluation that LoadRunner is much easier to use in a real world scenario. The Astra QuickTest Tool makes recording Business Processes and then parameterizing the data very easy. LoadRunner does emulate modem speeds accurately and has the ability to manage multiple user types (inside and outside of a browser). I recommend you do a side by side comparison of the tools and ignore the sales crap - both sales forces said they were the only "serious testing tool". For our App we found the Monitors that come with LoadRunner to be very powerful.

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unregistered posted 10-18-1999 07:18 PM Edit/Delete Message Copy This Message Reply w/Quote Search for more posts by BE Just to complete AdamA message, LoadRunner has also a very nice feature for testing web environments : "IPSpoofing".
Each simulated user gets its own IP address.
LoadRunner supplies an easy-to-use wizard to define as many IP addresses as you want for each injector machine.
So LoadRunner can really stress all the components of the web architecture :
Firewalls, routers, Load balancing...
All of these rely on the IP address to identify a user.
Other load testing tool will simulate all the users with the same IP address, which is not realistic and give false results...

Hope it helps...

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New Member

Posts: 2
Registered: Dec 1999
posted 12-02-1999 02:05 PM Click Here to See the Profile for SEG Edit/Delete Message Copy This Message Reply w/Quote Search for more posts by SEG If you are going with one-shot capture/replay, LoadRunner is just fine. Otherwise, Segue's Realizer and Test pieces are overwhelming improvements. The creation of an abstraction layer reduces man-hours by an order of magnitude for development systems or production systems that experience significant change. The Radar piece allows non-technical personnel to track QA failures with desktop replay. Expensive, yes. We paid $ 75,000. Worth every dime.

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QA grinder
unregistered posted 12-02-1999 09:08 PM Edit/Delete Message Copy This Message Reply w/Quote Search for more posts by QA grinder I don't know about that "accurate modem" comment for LoadRunner. I heard 2nd hand that a Mercury rep admitted that there modem simulation was essentially bogus - grabbing the whole file and then calculating a waiting time based on size before getting the next file. This sounds like faking it to me...

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unregistered posted 12-28-1999 02:24 PM Edit/Delete Message Copy This Message Reply w/Quote Search for more posts by JeffNyman I agree with most of the comments. LoadRunner is easier to use, but if you want more robust results and more scalability you should definitely go with SilkPerformer.

The modem times are much more accurate in SilkPerformer. LoadRunner seems to use some sort of algorithm to compute the times after the fact; it does take to long before you can deduce this on your own because the times are either inconsistent or do not match up with what you actually are seeing.

SilkPerformer also gives many more runtime settings that have a direct bearing on the results rather than just glitz while running. There are many options I have tried with LoadRunner that do work - but offer inconsistent results. I have had much better luck with SilkPerformer in this regard. This is not to say that LoadRunner was necessarily incorrect - just that it was much more inconsistent than SilkPerformer.

Also: SilkPerformer's integration of functional tests is much more smooth than in LoadRunner. I know that with the 5.0 version of LoadRunner, if you use a WinRunner script instead of an Astra script you lose some runtime setting options such as iterations. There is also the case that there are firm separations in LoadRunner's VUGen between database users and Web users and this makes for a lot of overhead. I have not had this problem with SilkPerformer because all scripts can be integrated.

As a caveat to all of the above: I am using WinRunner/LoadRunner 5.0 and SilkTest 5.0, SilkPerformer 3.0.

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unregistered posted 12-30-1999 09:39 AM Edit/Delete Message Copy This Message Reply w/Quote Search for more posts by LoadUser Mercury now ships LoadRunner 6.0.
This version has a new modem emulation that takes into consideration MANY modem issues and not like Segue bandwidth control

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unregistered posted 12-30-1999 11:40 AM Edit/Delete Message Copy This Message Reply w/Quote Search for more posts by JeffNyman I have not directly worked with LoadRunner 6.0 yet so I cannot comment too much on it, however from what I hear from Mercury and others who have used it, LoadRunner still does not handle burstiness and heavy-tailing with the use of a service demand law parameter - something that SilkPerformer does with ease. This really does not matter if you are working with traditional client/server, but for a Web-based solution it means everything.

I have also found that Mercury seems to equate the network transmission time with the network contention time in their internal logic. This is something that Segue does not (apparently) do and leads to much more accurate results in my opinion. I think a lot of this has to do with the fact that SilkPerformer uses a much more realistic internal setup for workload characterization than does LoadRunner.

Overall what I have found is that SilkPerformer is much more robust and much more reliant upon industry standard performance equations (knowingly or not) than is LoadRunner if you are doing a great deal of Web testing. For traditional client/server it is somewhat of a toss-up for me.

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unregistered posted 01-03-2000 02:11 PM Edit/Delete Message Copy This Message Reply w/Quote Search for more posts by PerformerExpert Another thing not mentioned is that Performer lets you set bounds and then compare against those bounds which I think is the workload characterization being mentioned. LoadRunner 6.0 has nothing that comes close to this. The repository information in SilkPerfomer is much better to -- much better than Mercury's BDE database setup.

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unregistered posted 01-17-2000 05:42 PM Edit/Delete Message Copy This Message Reply w/Quote Search for more posts by ewm In comparing the two products, I was led to believe that SilkPerformer's virtual user model was more accurate than that of Loadrunner's. A rep told me that because of the libraries that LR uses to connect to a web server, that LR can only service 4 connections per 50 virtual users simulated. Their explanation was along the lines that for every 50 virtual users simulated using LR , that only 4 would ever be concurrently connected. If running a load test with 100 users using LR then the web server would only ever experience max 8 connected users. Is this true? If it is, then how can the results gathered be validated?


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unregistered posted 01-18-2000 08:57 AM Edit/Delete Message Copy This Message Reply w/Quote Search for more posts by LR What do you think?
Do you think someone will buy LoadRunner if this was true?

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unregistered posted 02-02-2000 01:51 PM Edit/Delete Message Copy This Message Reply w/Quote Search for more posts by TK In regards to all those who posted here regarding the modem emulation between Silk and Merc, Mercury just released a two-DLL patch for modem emulation. It still uses an after-the-fact algorithm (just decompile the DLL's to find out) but it is much closer to what Silk is able to do. Since Mercury felt it necessary to do this it's obvious that much of what was said about alogrithms computing the timings after the fact was true since according to Mercury this "fix" gets rid of that. It doesn't completely though --- if you check out the timings and compare it with actual modem speeds, it's not nearly as close as Silk gets to the actual times.


  1. Silk performer::

    The cost of 100Vu is 50k USD.

    New Discovery:
    1. SilkPerformer comes for free.
    2. Pay for the Vu licenses only.
    3. Pay for SAM (Server Analysis Module). (20k USD)


    Only 25 Vu license is free with all protocols and only for 10 days from the day of installation.

  2. Things definitely have changed with Segue Licensing practices since Borland takeover. As previously mentioned by others Negotiating is extremely important.

    1)Borland uses it BRANDING to repackage pricing of SilkPerformer, (I think to compete with Merc. LR)

    2) Ask about all defferent types of licensing options.

    3)Borland support site has a customer service document that explains details on how they function (Useful document) and downloadable.