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author | Alan Stern <stern@rowland.harvard.edu> | 2007-02-19 20:52:45 (GMT) |
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committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-02-23 23:03:45 (GMT) |
commit | 17230acdc71137622ca7dfd789b3944c75d39404 (patch) | |
tree | 67eb75c5e8d254b2d5490ea9982efe73952f90d5 /drivers/usb/serial/ftdi_sio.h | |
parent | 28b9325e6ae45ffb5e99fedcafe00f25fcaacf06 (diff) | |
download | linux-17230acdc71137622ca7dfd789b3944c75d39404.tar.xz |
UHCI: Eliminate asynchronous skeleton Queue Headers
This patch (as856) attempts to improve the performance of uhci-hcd by
removing the asynchronous skeleton Queue Headers. They don't contain
any useful information but the controller has to read through them at
least once every millisecond, incurring a non-zero DMA overhead.
Now all the asynchronous queues are combined, along with the period-1
interrupt queue, into a single list with a single skeleton QH. The
start of the low-speed control, full-speed control, and bulk sublists
is determined by linear search. Since there should rarely be more
than a couple of QHs in the list, the searches should incur a much
smaller total load than keeping the skeleton QHs.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/serial/ftdi_sio.h')
0 files changed, 0 insertions, 0 deletions