Cache Memory Access Patterns in the GPU Architecture

Data exchange between a Central Processing Unit (CPU) and a Graphic Processing Unit (GPU) can be very expensive in terms of performance. The characterization of data and cache memory access patterns differ between a CPU and a GPU. The motivation of this research is to analyze the cache memory access patterns of GPU architectures and to potentially improve data exchange between a CPU and GPU. The methodology of this work uses Multi2Sim GPU simulator for AMD Radeon and NVIDIA Kepler GPU architectures. This simulator, used to emulate the GPU architecture in software, enables certain code modifications for the L1 and L2 cache memory blocks. Multi2Sim was configured to run multiple benchmarks to analyze and record how the benchmarks access GPU cache memory. The recorded results were used to study three main metrics: (1) Most Recently Used (MRU) and Least Recently Used (LRU) accesses for L1 and L2 caches, (2) Inter-warp and Intra-warp cache memory accesses in the GPU architecture for different sets of workloads, and (3) To record and compare the GPU cache access patterns for certain machine learning benchmarks with its general purpose counterparts

An ectopic pelvic kidney

BACKGROUND: If a kidney does not ascend as it should in normal fetal development, it remains in the pelvic area and is called a pelvic kidney. Often a person with a pelvic kidney will go through his/her whole life unaware of this condition, unless it is discovered during neonatal kidney ultrasound screening or if complications arise later in life due to this or a completely different reason and the condition is noted during investigations. Generally, this is not a harmful condition but it can lead to complications like in our case. With appropriate testing and treatment, if needed, an ectopic kidney should cause no serious long-term health complications and all that may be required for the patient is reassurance with advice to follow up at regular intervals. CASE REPORT: A 28-year-old male presented with recurrent pain in his lower left abdomen for one month and an episode of hematuria 3 days earlier accompanied by an attack of acute pain lasting for 3-4 hours. He gave a history of passing 2 small (about 5 mm each) calculi in his urine after the occurrence of hematuria, following which pain decreased in intensity. No history of fever was present. CONCLUSIONS: Although a simple ectopic kidney seldom causes symptoms, the association of malrotation of the renal pelvis with calculus increases the risk of hematuria and/or hydronephrosis, presenting with colicky pain as in the present case. The clinician should be aware of these in such a case. If asymptomatic, no treatment is required. However, the patient should be advised to have follow-up ultrasounds at regular intervals to detect complications like calculus, hydronephrosis, etc. With appropriate testing and treatment, if required, an ectopic kidney should not cause serious long-term health complications