From: "Matwey V. Kornilov" <matwey.kornilov@xxxxxxxxx> DMA cocherency slows the transfer down on systems without hardware coherent DMA. In order to demontrate this we introduce performance measurement facilities in patch 1 and fix the performance issue in patch 2 in order to obtain 5.5 times speedup. Changes since v1: * trace_pwc_handler_exit() call moved to proper place * detailed description added for commit 1 * additional output added to trace to track separate frames Matwey V. Kornilov (2): media: usb: pwc: Introduce TRACE_EVENTs for pwc_isoc_handler() media: usb: pwc: Don't use coherent DMA buffers for ISO transfer drivers/media/usb/pwc/pwc-if.c | 19 +++++++------ include/trace/events/pwc.h | 64 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 74 insertions(+), 9 deletions(-) create mode 100644 include/trace/events/pwc.h -- 2.16.4
