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Kernel API autotools checks are slow #9132

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ryao opened this issue Aug 7, 2019 · 5 comments
Closed

Kernel API autotools checks are slow #9132

ryao opened this issue Aug 7, 2019 · 5 comments
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Type: Building Indicates an issue related to building binaries Type: Performance Performance improvement or performance problem

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@ryao
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ryao commented Aug 7, 2019

Our Kernel API autotools checks invoke the kernel’s build system to build a kernel module as part of each check. I noticed that the Nvidia kernel driver also uses autotools and has a similar number of checks, but is much faster. It appears that Nvidia is invoking the compiler directly to speed up the process and that works for them. I imagine that might not work quite so well for testing for GPL symbol exports, but that technique likely could be adapted for the majority of our autotools checks to make things faster.

Speeding up the build system has always been a low priority for me, but I was recently troubleshooting what I thought to be a kernel bug that turned out to be the result of failing hardware causing miscompilation. While trying to figure it out, I had to sit through around a dozen full kernel and initramfs rebuilds for an entire day. At least an hour of that time seems to have been spent on autotools and after that experience, the build system performance suddenly feels like a higher priority to me. It is not high enough for me to do something right away, but it is high enough to have my attention. I am posting it here in case anyone wants to try to tackle this before I do. I am also self assigning it as a note to myself.

@ryao ryao added Type: Building Indicates an issue related to building binaries Type: Performance Performance improvement or performance problem labels Aug 7, 2019
@ryao ryao self-assigned this Aug 7, 2019
@perfinion
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another thing that would help i think is re-ordering some of the checks. a lot of the checks appear to be oldest kernel first with newest kernels at the end. which means the list gets longer and longer over time and it spends a lot of time "testing foo() with 2 params ... no", "testing foo with 3 params ... no", "with 4 params .. no", "with 5 ... yes". if we started with 5 then for most people things would probably be a lot faster just because there would be a lot less checks.

@c0d3z3r0
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c0d3z3r0 commented Aug 7, 2019

#8547

@c0d3z3r0
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c0d3z3r0 commented Aug 7, 2019

The time doubles by redundant calls of ./configure as described in #9135

@DeHackEd
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DeHackEd commented Aug 7, 2019

It would be a pretty major redesign, but if several files could be built at once it could be sped up significantly. Calling into the Kbuild system is expensive, and calling it once (or more!) for each test is what's killing it.

Being able to just make a single Makefile with all (most?) tests with a single make -k and collect the resulting mess after the fact could make it incredibly fast, but a management nightmare.

@behlendorf
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It appears that Nvidia is invoking the compiler directly to speed up the process and that works for them.

I think this is worth investigating since if it can be made it work we can hopefully avoid the need to make extensive (highly error prone) changes to the existing checks.

behlendorf added a commit to behlendorf/zfs that referenced this issue Sep 21, 2019
Reduce the time required for ./configure to perform the needed
KABI checks by allowing kbuild to compile multiple test cases in
parallel.  This was accomplished by splitting each test's source
code from the logic handling whether that code could be compiled
or not.

By introducing this split it's possible to minimize the number of
times kbuild needs to be invoked.  As importantly, it means all of
the tests can be built in parallel.  This does require a little extra
care since we expect some tests to fail, so the --keep-going (-k)
option must be provided otherwise some tests may not get compiled.
Furthermore, since a failure during the kbuild modpost phase will
result in an early exit; the final linking phase is limited to tests
which passed the initial compilation and produced an object file.

Once everything has been built the configure script proceeds as
previously.  The only significant difference is that it now merely
needs to test for the existence of a .ko file to determine the
result of a given test.  This vastly speeds up the entire process.

New test cases should use ZFS_LINUX_TEST_SRC to declare their test
source code and ZFS_LINUX_TEST_RESULT to check the result.  All of
the existing kernel-*.m4 files have been updated accordingly, see
config/kernel-current-time.m4 for a basic example.  The legacy
ZFS_LINUX_TRY_COMPILE macro has been kept to handle special cases
but it's use is not encouraged.

                  master (secs)   patched (secs)
                  -------------   ----------------
autogen.sh        61              68
configure         137             24  (~17% of current run time)
make -j $(nproc)  44              44
make rpms         287             150

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue openzfs#9132
behlendorf added a commit to behlendorf/zfs that referenced this issue Sep 26, 2019
Reduce the time required for ./configure to perform the needed
KABI checks by allowing kbuild to compile multiple test cases in
parallel.  This was accomplished by splitting each test's source
code from the logic handling whether that code could be compiled
or not.

By introducing this split it's possible to minimize the number of
times kbuild needs to be invoked.  As importantly, it means all of
the tests can be built in parallel.  This does require a little extra
care since we expect some tests to fail, so the --keep-going (-k)
option must be provided otherwise some tests may not get compiled.
Furthermore, since a failure during the kbuild modpost phase will
result in an early exit; the final linking phase is limited to tests
which passed the initial compilation and produced an object file.

Once everything has been built the configure script proceeds as
previously.  The only significant difference is that it now merely
needs to test for the existence of a .ko file to determine the
result of a given test.  This vastly speeds up the entire process.

New test cases should use ZFS_LINUX_TEST_SRC to declare their test
source code and ZFS_LINUX_TEST_RESULT to check the result.  All of
the existing kernel-*.m4 files have been updated accordingly, see
config/kernel-current-time.m4 for a basic example.  The legacy
ZFS_LINUX_TRY_COMPILE macro has been kept to handle special cases
but it's use is not encouraged.

                  master (secs)   patched (secs)
                  -------------   ----------------
autogen.sh        61              68
configure         137             24  (~17% of current run time)
make -j $(nproc)  44              44
make rpms         287             150

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue openzfs#9132
jgallag88 pushed a commit to jgallag88/zfs that referenced this issue Dec 6, 2019
Reduce the time required for ./configure to perform the needed
KABI checks by allowing kbuild to compile multiple test cases in
parallel.  This was accomplished by splitting each test's source
code from the logic handling whether that code could be compiled
or not.

By introducing this split it's possible to minimize the number of
times kbuild needs to be invoked.  As importantly, it means all of
the tests can be built in parallel.  This does require a little extra
care since we expect some tests to fail, so the --keep-going (-k)
option must be provided otherwise some tests may not get compiled.
Furthermore, since a failure during the kbuild modpost phase will
result in an early exit; the final linking phase is limited to tests
which passed the initial compilation and produced an object file.

Once everything has been built the configure script proceeds as
previously.  The only significant difference is that it now merely
needs to test for the existence of a .ko file to determine the
result of a given test.  This vastly speeds up the entire process.

New test cases should use ZFS_LINUX_TEST_SRC to declare their test
source code and ZFS_LINUX_TEST_RESULT to check the result.  All of
the existing kernel-*.m4 files have been updated accordingly, see
config/kernel-current-time.m4 for a basic example.  The legacy
ZFS_LINUX_TRY_COMPILE macro has been kept to handle special cases
but it's use is not encouraged.

                  master (secs)   patched (secs)
                  -------------   ----------------
autogen.sh        61              68
configure         137             24  (~17% of current run time)
make -j $(nproc)  44              44
make rpms         287             150

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes openzfs#8547 
Closes openzfs#9132
Closes openzfs#9341
tonyhutter pushed a commit to tonyhutter/zfs that referenced this issue Dec 26, 2019
Reduce the time required for ./configure to perform the needed
KABI checks by allowing kbuild to compile multiple test cases in
parallel.  This was accomplished by splitting each test's source
code from the logic handling whether that code could be compiled
or not.

By introducing this split it's possible to minimize the number of
times kbuild needs to be invoked.  As importantly, it means all of
the tests can be built in parallel.  This does require a little extra
care since we expect some tests to fail, so the --keep-going (-k)
option must be provided otherwise some tests may not get compiled.
Furthermore, since a failure during the kbuild modpost phase will
result in an early exit; the final linking phase is limited to tests
which passed the initial compilation and produced an object file.

Once everything has been built the configure script proceeds as
previously.  The only significant difference is that it now merely
needs to test for the existence of a .ko file to determine the
result of a given test.  This vastly speeds up the entire process.

New test cases should use ZFS_LINUX_TEST_SRC to declare their test
source code and ZFS_LINUX_TEST_RESULT to check the result.  All of
the existing kernel-*.m4 files have been updated accordingly, see
config/kernel-current-time.m4 for a basic example.  The legacy
ZFS_LINUX_TRY_COMPILE macro has been kept to handle special cases
but it's use is not encouraged.

                  master (secs)   patched (secs)
                  -------------   ----------------
autogen.sh        61              68
configure         137             24  (~17% of current run time)
make -j $(nproc)  44              44
make rpms         287             150

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes openzfs#8547
Closes openzfs#9132
Closes openzfs#9341
Conflicts:
	Makefile.am
	config/kernel-fpu.m4
tonyhutter pushed a commit to tonyhutter/zfs that referenced this issue Dec 27, 2019
Reduce the time required for ./configure to perform the needed
KABI checks by allowing kbuild to compile multiple test cases in
parallel.  This was accomplished by splitting each test's source
code from the logic handling whether that code could be compiled
or not.

By introducing this split it's possible to minimize the number of
times kbuild needs to be invoked.  As importantly, it means all of
the tests can be built in parallel.  This does require a little extra
care since we expect some tests to fail, so the --keep-going (-k)
option must be provided otherwise some tests may not get compiled.
Furthermore, since a failure during the kbuild modpost phase will
result in an early exit; the final linking phase is limited to tests
which passed the initial compilation and produced an object file.

Once everything has been built the configure script proceeds as
previously.  The only significant difference is that it now merely
needs to test for the existence of a .ko file to determine the
result of a given test.  This vastly speeds up the entire process.

New test cases should use ZFS_LINUX_TEST_SRC to declare their test
source code and ZFS_LINUX_TEST_RESULT to check the result.  All of
the existing kernel-*.m4 files have been updated accordingly, see
config/kernel-current-time.m4 for a basic example.  The legacy
ZFS_LINUX_TRY_COMPILE macro has been kept to handle special cases
but it's use is not encouraged.

                  master (secs)   patched (secs)
                  -------------   ----------------
autogen.sh        61              68
configure         137             24  (~17% of current run time)
make -j $(nproc)  44              44
make rpms         287             150

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes openzfs#8547
Closes openzfs#9132
Closes openzfs#9341
Conflicts:
	Makefile.am
	config/kernel-fpu.m4
stevijo pushed a commit to stevijo/zfs that referenced this issue Jan 12, 2020
Reduce the time required for ./configure to perform the needed
KABI checks by allowing kbuild to compile multiple test cases in
parallel.  This was accomplished by splitting each test's source
code from the logic handling whether that code could be compiled
or not.

By introducing this split it's possible to minimize the number of
times kbuild needs to be invoked.  As importantly, it means all of
the tests can be built in parallel.  This does require a little extra
care since we expect some tests to fail, so the --keep-going (-k)
option must be provided otherwise some tests may not get compiled.
Furthermore, since a failure during the kbuild modpost phase will
result in an early exit; the final linking phase is limited to tests
which passed the initial compilation and produced an object file.

Once everything has been built the configure script proceeds as
previously.  The only significant difference is that it now merely
needs to test for the existence of a .ko file to determine the
result of a given test.  This vastly speeds up the entire process.

New test cases should use ZFS_LINUX_TEST_SRC to declare their test
source code and ZFS_LINUX_TEST_RESULT to check the result.  All of
the existing kernel-*.m4 files have been updated accordingly, see
config/kernel-current-time.m4 for a basic example.  The legacy
ZFS_LINUX_TRY_COMPILE macro has been kept to handle special cases
but it's use is not encouraged.

                  master (secs)   patched (secs)
                  -------------   ----------------
autogen.sh        61              68
configure         137             24  (~17% of current run time)
make -j $(nproc)  44              44
make rpms         287             150

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes openzfs#8547
Closes openzfs#9132
Closes openzfs#9341
(cherry picked from commit 608f874)
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
tonyhutter pushed a commit that referenced this issue Jan 23, 2020
Reduce the time required for ./configure to perform the needed
KABI checks by allowing kbuild to compile multiple test cases in
parallel.  This was accomplished by splitting each test's source
code from the logic handling whether that code could be compiled
or not.

By introducing this split it's possible to minimize the number of
times kbuild needs to be invoked.  As importantly, it means all of
the tests can be built in parallel.  This does require a little extra
care since we expect some tests to fail, so the --keep-going (-k)
option must be provided otherwise some tests may not get compiled.
Furthermore, since a failure during the kbuild modpost phase will
result in an early exit; the final linking phase is limited to tests
which passed the initial compilation and produced an object file.

Once everything has been built the configure script proceeds as
previously.  The only significant difference is that it now merely
needs to test for the existence of a .ko file to determine the
result of a given test.  This vastly speeds up the entire process.

New test cases should use ZFS_LINUX_TEST_SRC to declare their test
source code and ZFS_LINUX_TEST_RESULT to check the result.  All of
the existing kernel-*.m4 files have been updated accordingly, see
config/kernel-current-time.m4 for a basic example.  The legacy
ZFS_LINUX_TRY_COMPILE macro has been kept to handle special cases
but it's use is not encouraged.

                  master (secs)   patched (secs)
                  -------------   ----------------
autogen.sh        61              68
configure         137             24  (~17% of current run time)
make -j $(nproc)  44              44
make rpms         287             150

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #8547
Closes #9132
Closes #9341
Conflicts:
	Makefile.am
	config/kernel-fpu.m4
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