Re: [Qemu-devel] [PATCH V2] qemu-img: make convert async

[Peter Lieven]

Am 27.02.2017 um 22:09 schrieb Eric Blake:
> On 02/27/2017 05:03 AM, Peter Lieven wrote:
> > the convert process is currently completely implemented with sync operations.
> > That means it reads one buffer and then writes it. No parallelism and each sync
> > request takes as long as it takes until it is completed.
> >
> > This patches introduces 2 new cmdline parameters. The -m parameter to specify
> > the number of coroutines running in parallel (defaults to 8). And the -W 
> > paremeter to
> s/paremeter/parameter/
>
> > allow qemu-img to write to the target out of order rather than sequential. This 
> > improves
> > performance as the writes do not have to wait for each other to complete.
> >
> > Signed-off-by: Peter Lieven <address@hidden>
> > ---
> > @@ -1798,7 +1908,7 @@ static int img_convert(int argc, char **argv)
> >               {"image-opts", no_argument, 0, OPTION_IMAGE_OPTS},
> >               {0, 0, 0, 0}
> >           };
> > -        c = getopt_long(argc, argv, "hf:O:B:ce6o:s:l:S:pt:T:qn",
> > +        c = getopt_long(argc, argv, "hf:O:B:ce6o:s:l:S:pt:T:qnm:W",
> >                           long_options, NULL);
> >           if (c == -1) {
> >               break;
> > @@ -1890,6 +2000,18 @@ static int img_convert(int argc, char **argv)
> >           case 'n':
> >               skip_create = 1;
> >               break;
> > +        case 'm':
> > +            num_coroutines = atoi(optarg);
> atoi() should be avoided. It has no error checking, so it treats '-m 1'
> and '-m 1k' identically.  You are a bit justified in that '-m junk' gets
> treated like '-m 0' and rejected, but it's still a poor error message in
> that case.

would you use qemu_strtoul or parse_uint instead?

Kevin, shall I send a V3?

Peter