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Subject[PATCH v3 0/2] media: usb: pwc: Don't use coherent DMA buffers for ISO transfer
Date
From: "Matwey V. Kornilov" <matwey.kornilov@gmail.com>

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 4 times speedup.

Changes since v2:
* use dma_sync_single_for_cpu() to achive better performance
* remeasured performance

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 | 54 +++++++++++++++++++++++++++--------
include/trace/events/pwc.h | 64 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 106 insertions(+), 12 deletions(-)
create mode 100644 include/trace/events/pwc.h

--
2.16.4

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