Re: [libvirt] [PATCH] libxl: don't hardcode scheduler weight

On 02/22/2018 05:20 PM, Jim Fehlig wrote: > Long ago in commit dfa1e1dd53 the scheduler weight was accidentally > hardcoded to 1000. Weight is a setting with no unit since it is > relative to the weight of other domains. If no weight is specified, > libxl defaults to 256. > > Instead of hardcoding the weight to 1000, honor any <shares> specified > in <cputune>. libvirt's notion of shares is synonomous to libxl's > scheduler weight setting. If shares is unspecified, defer default > weight setting to libxl. > > Removing the hardcoded weight required some test fixup. While at it, > add an explicit test for <shares> conversion to scheduler weight. > > Signed-off-by: Jim Fehlig <jfehlig(a)suse.com&gt; > --- > > Honoring <shares> specified by the user is certainly desirable, > but I'm not sure about changing the default weight. One problematic > scenario that came to mind: Several domains started by pre-patch > libvirtd with weight=1000, update libvirtd with patch, start more > domains with weight=256. The pre-patch domains unknowingly have > a weight nearly 4 times that of post-patch domains. Put 'em all on a diet. Don't try to do it overnight though because that never works and it makes them all hangry... Slowly try to have them lose weight over the course a few months and in no time they'll be slim, trim, and less cumbersome. Whether they'll be happy - who knows ;-)

> > src/libxl/libxl_conf.c | 4 +- > tests/libxlxml2domconfigdata/basic-hvm.json | 2 +- > tests/libxlxml2domconfigdata/basic-pv.json | 2 +- > tests/libxlxml2domconfigdata/cpu-shares-hvm.json | 89 ++++++++++++++++++++++ > tests/libxlxml2domconfigdata/cpu-shares-hvm.xml | 39 ++++++++++ > tests/libxlxml2domconfigdata/moredevs-hvm.json | 2 +- > tests/libxlxml2domconfigdata/multiple-ip.json | 2 +- > .../libxlxml2domconfigdata/variable-clock-hvm.json | 2 +- > tests/libxlxml2domconfigdata/vnuma-hvm.json | 2 +- > tests/libxlxml2domconfigtest.c | 1 + > 10 files changed, 138 insertions(+), 7 deletions(-) > Perhaps this is a "news" worthy type change along with the caveat about those more weighty domains that were allowed to feed at the trough without being limited.