From sagar at uab.edu Tue Mar 31 17:13:32 2015 From: sagar at uab.edu (Sagar Thapaliya) Date: Tue, 31 Mar 2015 21:13:32 +0000 Subject: [Disksim-users] problem submitting concurrent I/O requests to DiskSim under system simulator (slave) mode Message-ID: <1427836412195.25309@uab.edu> Hi, I am trying to understand how to use DiskSim for a shared system, while using it under system simulator (i.e. DiskSim as slave). I am new to DiskSim, so had problem figuring something out, and wondering if I'm even doing it the right way. I would really appreciate if you would be able to help me with the following question and problem I faced: Question on concurrent access: Is it possible to submit a new request to DiskSim before an outstanding request is processed? Here, I basically want to create a situation where there are multiple concurrent IO request in the disk queue. Details: And here are details of what I was trying to achieve, steps I have tried with syssim_driver.c code, and the problem I have faced: ---------- Original arrival of syssim: I noticed that the example code syssim_driver.c generates new IO requests only after an existing request is processed till its completion. Modified arrival with overlap: I changed the example code to add second requests before the first request is complete (e.g., before calling disksim_interface_internal_event). Used disksim_request.id to track request's progress: I also wanted an ability to track when a specific I/O request completed. So, I utilized the field "id" of disksim_request: set a unique value to each request in main method, and read values "id" and completion time "t" in method syssim_report_completion. Problem: - Original arrival of syssim: worked fine: id and t were unique for each requests, and values looked correct. - Modified arrival with overlap: Had this problem - each time syssim_report_completion was invoked, its parameter disksim_request *r seemed to have same value (r.id, r.bytecount, r.start). I performed these tests with disksim 4.0, with hdd and ssd models (FlashSim). ---------- Could you suggest if I am doing anything wrong here? Or is it possible that this problem is coming due to known limitation of Disksim? Regards, Sagar Thapaliya -------------- next part -------------- An HTML attachment was scrubbed... URL: