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SubjectRe: First kernel patch (optimization)
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On Tue, Sep 15, 2015 at 12:53 PM, Eric Curtin <ericcurtin17@gmail.com> wrote:
> Signed-off-by: Eric Curtin <ericcurtin17@gmail.com>
>
> diff --git a/tools/usb/usbip/src/usbip_detach.c b/tools/usb/usbip/src/usbip_detach.c
> index 05c6d15..9db9d21 100644
> --- a/tools/usb/usbip/src/usbip_detach.c
> +++ b/tools/usb/usbip/src/usbip_detach.c
> @@ -47,7 +47,9 @@ static int detach_port(char *port)
> uint8_t portnum;
> char path[PATH_MAX+1];
>
> - for (unsigned int i = 0; i < strlen(port); i++)
> + unsigned int port_len = strlen(port);
> +
> + for (unsigned int i = 0; i < port_len; i++)
> if (!isdigit(port[i])) {
> err("invalid port %s", port);
> return -1;
>
> --

Hi Eric,

This is fine, but what kind of wimpy compiler optimizer will not move
the constant initializer out of the loop? I bet if you compare binary
sizes/code it will be exactly the same, and you added some characters
of code. Reorganizing code for readability is fine, but for compiler
(in)efficiency seems like a bad idea.

Regards, Steve


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