From: Russell King <rmk@arm.linux.org.uk>
To: Jiri Kosina <jkosina@suse.cz>
Cc: linux-input@vger.kernel.org, linux-usb@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Henrik Rydberg <rydberg@euromail.se>
Subject: Re: USB interrupt times
Date: Wed, 15 Aug 2012 10:15:54 +0100 [thread overview]
Message-ID: <20120815091554.GD7105@flint.arm.linux.org.uk> (raw)
In-Reply-To: <alpine.LNX.2.00.1208151102040.7026@pobox.suse.cz>
On Wed, Aug 15, 2012 at 11:02:37AM +0200, Jiri Kosina wrote:
> On Tue, 14 Aug 2012, Russell King wrote:
>
> > > Actually, Henrik (added to CC) has been doing some latency improvements
> > > both for input core in general, and for HID devices as well lately. I
> > > still have his patchset in my to-review queue, as I have just came back
> > > from offline vacation, but the patch below definitely can't hurt and
> > > should significantly lower the time spent in handling the irq for hid
> > > device in common situation (i.e. noone listening for debugfs events).
> > >
> > > Could you please measure how much it helps on your system?
> >
> > Ok, it looks like it's changed the maximum USB interrupt execution
> > time from around 364us to 255us.
> >
> > If I also do a similar trick with the debug code in hid_input_report()
> > then I get down to 212us - iow, something like the patch below.
>
> Are you testing with kernel that contains b94e3c94aae04 already? That
> should cover that case.
No - the kernel I'm dealing with is unfortunately based upon v3.5.0-rc5
with many other patches on top (which add support for this platform.)
However, I'll pick that commit into this tree.
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of:
next prev parent reply other threads:[~2012-08-15 9:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-14 10:39 USB interrupt times Russell King
2012-08-14 10:54 ` Jiri Kosina
[not found] ` <alpine.LNX.2.00.1208141250020.12490-ztGlSCb7Y1iN3ZZ/Hiejyg@public.gmane.org>
2012-08-14 12:18 ` Russell King
[not found] ` <20120814121804.GC7105-f404yB8NqCZvn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2012-08-14 18:30 ` Henrik Rydberg
2012-08-15 9:02 ` Jiri Kosina
2012-08-15 9:15 ` Russell King [this message]
2012-08-14 12:31 ` Oliver Neukum
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