Debian: qat1.7.l driver package build uses a single CPU and builds the driver twice

[M. Vefa Bicakci]

Brief Description
-----------------
The Debian build for the QAT device driver uses a single CPU and builds the driver twice due to the following reasons:

The build makefile snippet (debian/rules) calls "make" directly instead of calling "$(MAKE)". The latter allows inheriting the parent make instance's parallel-job settings, but the former does not. This translates to the build system using a single CPU to build the driver. To fix this issue, the following:

  override_dh_auto_build:
          make
          make sample-all

should be replaced with:

  override_dh_auto_build:
          $(MAKE)
          $(MAKE) sample-all

Finally, the debian/rules makefile snippet does not disable the dh_auto_test hook (it does not override this hook). This causes the build system to call "make -j1 check VERBOSE=1" after the main build, but this rebuilds the whole driver one more time, also using a single CPU, due to the use of "-j1" and due to the apparent fact that the "check" target is recognized by the QAT driver's makefiles as another target to rebuild everything. Quoting from the driver's Makefile.in:

  ALL_TARGETS = qat-driver-all quickassist-all adf-rl-all adf-ctl-all qat-service-all
  ...
  check-am: all-am
  check: check-am
  all-am: Makefile config.h all-local
  ...
  all-local: $(ALL_TARGETS)

The resolution of this issue is to define an override for dh_auto_test (in the debian/rules file) that does nothing:

override_dh_auto_test:
       true

Severity
--------
Minor: The identified issues increase the build time by about 13~14 minutes (~ 2 x 7 minutes, because of the standard and preempt-rt variants of the driver build). This is admittedly a minor build optimization issue.

Note
----
I did not fill out the full bug report template. This bug report exists just so that I can publish a commit fixing this issue.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/kernel/+/857741

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/kernel/+/857741
Committed: https://opendev.org/starlingx/kernel/commit/0d091fe7207497c4b7444e420c2da0d56f5cf306
Submitter: "Zuul (22348)"
Branch: master

commit 0d091fe7207497c4b7444e420c2da0d56f5cf306
Author: M. Vefa Bicakci <email address hidden>
Date: Tue Sep 13 21:22:17 2022 +0000

    kernel-modules/qat17: Debian: Increase build speed

    Modify the debian/rules file belonging to the qat device driver so that
    the build lets child make instances use make's job server by calling
    $(MAKE) instead of "make" in the debian/rules file. This allows the
    child make process to utilize more than one CPU.

    Also, remove the call to dh_auto_test during the build by defining a
    make target named "override_dh_auto_test". Allowing dh_auto_test to be
    called makes the Debian build system call "make -j1 check VERBOSE=1".
    However, in the QAT driver's "Makefile.in", the "check" target
    indirectly depends on the "all-local" target, which in turn rebuilds all
    of the code. All this to say, this issue causes driver to be built one
    more time, this time in single-job mode (due to the -j1).

    Below are the durations of builds carried out in a 12-CPU virtual
    machine:

    Without this commit:
      Build needed 00:09:24, 315160k disk space

    With $(MAKE) instead of make:
      Build needed 00:05:04, 321484k disk space

    With $(MAKE) instead of make and with override_dh_auto_test:
      Build needed 00:02:33, 321928k disk space

    Verification
    - "build-pkgs -c -p qat1.7.l" continues to work, but takes a lot less
      time to finish.

    Closes-Bug: 1989601
    Change-Id: I825e0f482ad9a73f9b78c087ca3c7bb57a37f4bd
    Signed-off-by: M. Vefa Bicakci <email address hidden>