On Mon, Mar 6, 2023 at 8:42 AM Tony Lindgren <tony@xxxxxxxxxxx> wrote: > > * Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> [230228 08:01]: > > Any idea why the performance drop is so big? > > Maybe lots of interrupts and dma not being used for musb in this case? Using "irqtop -d 1", I get the following results: 3.18.1 LATENCY_OFF (16 ports): ca. 1000 IRQs/s INTC 17 47400000.dma-controller 3.18.1 LATENCY_ON (16 ports): ca. 4000 IRQs/s INTC 17 47400000.dma-controller 6.2.1 LATENCY_OFF (16 ports): ca. 300 IRQs/s INTC 17 47400000.dma-controller 6.2.1 LATENCY_ON (16 ports): ca. 1000 IRQs/s INTC 17 47400000.dma-controller #zcat /proc/config.gz | grep CPP CONFIG_USB_TI_CPPI41_DMA=y CONFIG_TI_CPPI41=y Looks like 3.18.1 can handle more interrupts than 6.2.1. Yegor
