From: <Mark_Lindholm@Dell.com> - 2013-08-22 14:40:38
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I am running Windows Server 2008 R2. Running Dynamo directly (no network). OMETER 2006.07.27 Mark. From: Vedran Degoricija [mailto:ve...@ya...] Sent: Wednesday, August 21, 2013 9:17 PM To: Lindholm, Mark; iom...@li... Subject: Re: [Iometer-user] Missing Writes with 99/1 Read/Write ratio Hi Mark, Yes, unfortunately, this consistent. The higher the R/W difference (excepting 100/0), the lower the chances of hitting the smaller valued I/O. This should be addressed. :( I am curious, under what OS was Dynamo executing? Thanks, Ved From: "Mark_Lindholm@Dell.com<mailto:Mark_Lindholm@Dell.com>" <Mark_Lindholm@Dell.com<mailto:Mark_Lindholm@Dell.com>> To: ve...@ya...<mailto:ve...@ya...>; iom...@li...<mailto:iom...@li...> Sent: Wednesday, August 21, 2013 7:06 AM Subject: RE: [Iometer-user] Missing Writes with 99/1 Read/Write ratio In the example I attached I was running for 60 seconds for each Q depth. So for some of the workloads/Qdepth I was not getting a single write in 60 seconds of run. I put a bus analyzer on when I was running and it confirmed the 1% writes, were sometimes not there. I also tried other ratios, like 98/2, 97,3 and they worked but they would not give me the exact ratio asked for (according to the bus analyzer). So if I asked for 98/2, I might get 99/1 or 97/3. Following the same logic if I ask for 99/1 I sometimes get 2% writes and sometimes get 0%? Mark. From: Vedran Degoricija [mailto:ve...@ya...] Sent: Tuesday, August 20, 2013 11:28 PM To: Lindholm, Mark; iom...@li...<mailto:iom...@li...> Subject: Re: [Iometer-user] Missing Writes with 99/1 Read/Write ratio Hi Mark, This is interesting. How long do you typically run each test for? I suspect the problem is with the fairness of the indexing algorithm into the access_grid (see IOAccess.*) that represent the read/write mix. With one entry being either a write or a read, it has really low chances of getting hit. Unless something is broken, we'd need to look into a fairer algorithm or you run for a longer time. Ved From: "Mark_Lindholm@Dell.com<mailto:Mark_Lindholm@Dell.com>" <Mark_Lindholm@Dell.com<mailto:Mark_Lindholm@Dell.com>> To: iom...@li...<mailto:iom...@li...> Sent: Tuesday, August 6, 2013 3:41 PM Subject: [Iometer-user] Missing Writes with 99/1 Read/Write ratio I have attached a simple script that repeats a 4K Sequential 99/1 Read/Write with incrementing Q depth. I have also attached the test output, which shows that the writes are sometimes missing. If I change the Read/Write ratio to anything other than 99/1 (or 1/99 the reads will sometimes stop). Any idea why this does not work correctly? Mark. ------------------------------------------------------------------------------ Introducing Performance Central, a new site from SourceForge and AppDynamics. Performance Central is your source for news, insights, analysis and resources for efficient Application Performance Management. Visit us today! http://pubads.g.doubleclick.net/gampad/clk?id=48897511&iu=/4140/ostg.clktrk _______________________________________________ Iometer-user mailing list Iom...@li...<mailto:Iom...@li...> https://lists.sourceforge.net/lists/listinfo/iometer-user |