From:   =?UTF-8?q?Andr=C3=A9=20Almeida?= <andrealmeid@collabora.com>
To:     Benjamin Tissoires <benjamin.tissoires@redhat.com>,
        Jiri Kosina <jikos@kernel.org>, linux-input@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel@collabora.com
Cc:     =?UTF-8?q?Andr=C3=A9=20Almeida?= <andrealmeid@collabora.com>
Subject: [PATCH 0/1] hidraw: Improve subsytem throughput
Date:   Tue, 30 Nov 2021 10:29:56 -0300
Message-Id: <20211130132957.8480-1-andrealmeid@collabora.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

Hi,

In a discussion about SteamVR for Linux[0], users found out that
modifying hidraw code would lead to more stable frame per seconds. This
patch aims to fix a bottleneck at hidraw subsystem to increase the
system throughput when using a lot of HIDs at same time.

I created an artificial benchmark tool[1] to test this. It issues a lot of
ioctls in parallel for 5 HID devices. While the original kernel took
around 1570 nsecs to complete all the calls, after applying this patch
it took around 412 nsecs, almost 4x faster.

Thanks,
	André

[0] https://github.com/ValveSoftware/SteamVR-for-Linux/issues/21
[1] https://gist.github.com/andrealmeid/b495999b8efce3c741e14a709a21e49b

André Almeida (1):
  HID: hidraw: Replace hidraw device table mutex with a rwsem

 drivers/hid/hidraw.c | 34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

-- 
2.34.1