If you're trying to minimize latency you want the smallest values that work reliably (no over/underruns) and with acceptable overhead. So, does that mean if we have large product of fusb_block_size and fusb_nblock, then the theoretical maximum delay will be increased? Since we use complex 16 bit samples, the sample size is
Where:f(x,y) is depends on the data in the buffer and it is at least x and at most y and fs is the sampling frequency. Tu = f(512, fusb_block_size*fusb_nblock) / (fs*sample_size ) As a paper mentions, the USB delay (Tu) is according to the equation: We can calculate the latency introduced by the USB since the USB packet is only sent when we have a sufficient amount of data collected in the USRP buffer, i.e., the smallest allowed USB packet is 512 byte, and the largest one is specified by the user by two parameters, fusb_nblock and fusb_block_size. Highest reported total DPC routine time (%): 0.130994ĭriver with highest DPC total execution time: Wdf01000.sys - Kernel Mode Driver Framework Runtime, Microsoft Corporation Highest DPC routine execution time (µs): 361.8050ĭriver with highest DPC routine execution time: Wdf01000.sys - Kernel Mode Driver Framework Runtime, Microsoft Corporation Highest reported total ISR routine time (%): 0.009266ĭriver with highest ISR total time: Wdf01000.sys - Kernel Mode Driver Framework Runtime, Microsoft CorporationĭPC routines are part of the interrupt servicing dispatch mechanism and disable the possibility for a process to utilize the CPU while it is interrupted until the DPC has finished execution. Highest ISR routine execution time (µs): 54.138333ĭriver with highest ISR routine execution time: Wdf01000.sys - Kernel Mode Driver Framework Runtime, Microsoft Corporation Interrupt service routines are routines installed by the OS and device drivers that execute in response to a hardware interrupt signal. Highest measured interrupt to DPC latency (µs): 238.10Īverage measured interrupt to DPC latency (µs): 1.566288 Highest measured interrupt to process latency (µs): 298.30Īverage measured interrupt to process latency (µs): 6.275653 This includes the scheduling and execution of a DPC routine, the signaling of an event and the waking up of a usermode thread from an idle wait state in response to that event. The interrupt to process latency reflects the measured interval that a usermode process needed to respond to a hardware request from the moment the interrupt service routine started execution. MEASURED INTERRUPT TO USER PROCESS LATENCIES
0 kommentar(er)
