Re: [PATCH v2 01/13] qtest/migration-test.c: Add postcopy tests with compress enabled

[Juan Quintela <quintela@redhat.com>]

Lukas Straub <lukasstraub2@web.de> wrote:
> On Thu, 20 Apr 2023 12:20:25 +0200
> Juan Quintela <quintela@redhat.com> wrote:
>
>> Lukas Straub <lukasstraub2@web.de> wrote:
>> > Add postcopy tests with compress enabled to ensure nothing breaks
>> > with the refactoring in the next commits.
>> >
>> > preempt+compress is blocked, so no test needed for that case.
>> >
>> > Signed-off-by: Lukas Straub <lukasstraub2@web.de>  
>> 
>> Reviewed-by: Juan Quintela <quintela@redhat.com>
>> 
>> And I wanted to removed the old compression code and it gets new users.  Sniff.
>
> Who know how many compress threads users are out there...

Not too much.
We broke it during development and nobody found it.

And the reason that I wrote the multifd-zlib compression code was
because I was not able to get a migration-test working with compression,
so ....

> By the way, I'm not against deprecating compress threads in the long
> run. I'm already working on (cleanly :)) adding colo support with
> multifd.

Ok, then I will still put the deprecate comment there.


>> > ---
>> >  tests/qtest/migration-test.c | 83 +++++++++++++++++++++++-------------
>> >  1 file changed, 53 insertions(+), 30 deletions(-)
>> >
>> > diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
>> > index 1f2a019ce0..930cb4f29d 100644
>> > --- a/tests/qtest/migration-test.c
>> > +++ b/tests/qtest/migration-test.c
>> > @@ -1127,6 +1127,36 @@ test_migrate_tls_x509_finish(QTestState *from,
>> >  #endif /* CONFIG_TASN1 */
>> >  #endif /* CONFIG_GNUTLS */
>> >
>> > +static void *
>> > +test_migrate_compress_start(QTestState *from,
>> > +                            QTestState *to)
>> > +{
>> > +    migrate_set_parameter_int(from, "compress-level", 1);
>> > +    migrate_set_parameter_int(from, "compress-threads", 4);
>> > +    migrate_set_parameter_bool(from, "compress-wait-thread", true);
>> > +    migrate_set_parameter_int(to, "decompress-threads", 4);
>> > +
>> > +    migrate_set_capability(from, "compress", true);
>> > +    migrate_set_capability(to, "compress", true);
>> > +
>> > +    return NULL;
>> > +}  
>> 
>> Independently of this patch, we need to change this test to use 4
>> compression tests and 3 decompression or anything that is not the same
>> number in both sides.
>> 
>> I was complaining about this and when I arrived to the end of the path
>> found that this was code movement.
>> 
>> Later, Juan.
>> 
>
> Oops, forgot to mention, the test is based on this patch
> https://lore.kernel.org/qemu-devel/2f4abb67cf5f3e1591b2666676462a93bdd20bbc.1680618040.git.lukasstraub2@web.de/
>
> Will probably carry the patch with this series then. So you mean 4
> compress _threads_ and 3 decompress _threads_?

Yeap.

Later, Juan.