Re: [Xen-devel] [PATCH] xm,xend: flesh out xm sched-sedf

[Ewan Mellor <ewan@xxxxxxxxxxxxx>]

On Tue, Mar 07, 2006 at 05:42:43PM -0600, Ryan Harper wrote:

> This patch
> 
> -Displays[1] current parameters for running domains ala xm list
> -Allow users to set[2] one or more parameters[3] without having to 
>  provide values for parameters they do not wish to change
> -Adds additional testing of sched-sedf via new xm-test testcases.
> 
> With this patch applied, test 02_sedf_period_lower_neg.py exposes a
> bug[4].  I'll follow up this email with a patch for the bug.

Applied, complete with FIXME.

> FIXME: this can probably go away if someone points me to the proper way.
> +    def domid_match(domid, info):
> +        d = ""
> +        f = ""
> +        try:
> +            d = int(domid)
> +            f = 'dom'
> +        except:
> +            d = domid 
> +            f = 'name'
> +
> +        return (d == info[f])

You can probably just go with

def domid_match(domid, info):
    return domid == info['name'] || domid == str(info['dom'])

and then, because I prefer to use None when I really mean 'value unspecified',
and because I'd want to roll the test for 'unspecified' into domid_match, I'd
do

def domid_match(domid, info):
    return domid is None || domid == info['name'] || domid == str(info['dom'])

and change the domid = -1 to domid = None, which then means that  

> +        if domid == '-1' or domid_match(domid, d):

loses the first test.  Neater, IMHO, mainly because now we've got the one test,
we can use filter and get rid of the for loop and the if statement altogether:

doms = filter(lambda x : domid_match(domid, x),
              [parse_doms_info(dom) for dom in getDomains("")])

(It's a real shame that Guido's eschewed a decent partial-application syntax,
because Python's list comprehensions are really nice, but some extra syntax for
partial applications would make this example much nicer.)

I'll let you try this; if you like it, send a patch back.

Cheers,

Ewan.

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