From: "Matwey V. Kornilov" <matwey@sai.msu.ru>
To: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: "Matwey V. Kornilov" <matwey.kornilov@gmail.com>,
tfiga@chromium.org, laurent.pinchart@ideasonboard.com,
matwey@sai.msu.ru, stern@rowland.harvard.edu,
ezequiel@collabora.com, hdegoede@redhat.com, hverkuil@xs4all.nl,
mchehab@kernel.org, rostedt@goodmis.org, mingo@redhat.com,
isely@pobox.com, bhumirks@gmail.com, colin.king@canonical.com,
kieran.bingham@ideasonboard.com, keiichiw@chromium.org
Subject: [PATCH v3 0/2] media: usb: pwc: Don't use coherent DMA buffers for ISO transfer
Date: Thu, 9 Aug 2018 12:33:05 +0300 [thread overview]
Message-ID: <20180809093307.6001-1-matwey@sai.msu.ru> (raw)
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
next reply other threads:[~2018-08-09 11:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-09 9:33 Matwey V. Kornilov [this message]
2018-08-09 9:33 ` [PATCH v3 1/2] media: usb: pwc: Introduce TRACE_EVENTs for pwc_isoc_handler() Matwey V. Kornilov
2018-08-09 13:49 ` Steven Rostedt
2018-08-09 9:33 ` [PATCH v3 2/2] media: usb: pwc: Don't use coherent DMA buffers for ISO transfer Matwey V. Kornilov
2018-08-09 9:51 ` Laurent Pinchart
2018-08-09 10:08 ` Matwey V. Kornilov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180809093307.6001-1-matwey@sai.msu.ru \
--to=matwey@sai.msu.ru \
--cc=bhumirks@gmail.com \
--cc=colin.king@canonical.com \
--cc=ezequiel@collabora.com \
--cc=hdegoede@redhat.com \
--cc=hverkuil@xs4all.nl \
--cc=isely@pobox.com \
--cc=keiichiw@chromium.org \
--cc=kieran.bingham@ideasonboard.com \
--cc=laurent.pinchart@ideasonboard.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=matwey.kornilov@gmail.com \
--cc=mchehab@kernel.org \
--cc=mingo@redhat.com \
--cc=rostedt@goodmis.org \
--cc=stern@rowland.harvard.edu \
--cc=tfiga@chromium.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox