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latency comment

Luis Ardila 8 years ago
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1 changed files with 9 additions and 1 deletions
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      paper.tex

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paper.tex

@@ -292,7 +292,15 @@ The total latency is decreased
 The distribution of latency is shown in Figure \ref{fig:latency}.
 
 %% EMERGENCY TEXT if we don't manage to fix the latency problem
-The round-trip time of a memory read request issued from the CPU to the FPGA is less then 1 $\mu$s. Therefore, the current performance bottleneck lies in the execution of DirectGMA functions. 
+The round-trip time of a memory read request issued from the CPU to the FPGA is less then 1 $\mu$s. Therefore, the current performance bottleneck lies in the execution of DirectGMA functions.
+% LA: Is this from a reference or we meassure it?
+ 
+% LA: This time that you are showing here does not correlate with the measurements we were taking.
+% this 1 us is the round time inside the FPGA for the memory read, totally dependent on the FPGA,
+% 
+% The times we are plotting in FIG 5 are the round trips inside the GPU not the FPGA
+% Yesterday I took the same measurement with the System Memory (CPU) and the values are not that different,
+% you can see the file out_cpu.txt values clustering around 150 us (CPU) instead of 170 us (GPU)