Re: PostgreSQL cannot be compiled on RISC-V

On Sat, Nov 19, 2016 at 10:08:07PM -0500, Tom Lane wrote:
> "Richard W.M. Jones" <rjones(at)redhat(dot)com> writes:
> > ../../../src/include/storage/s_lock.h:890:2: error: #error PostgreSQL does not have native spinlock support on this platform. To continue the compilation, rerun configure using --disable-spinlocks. However, performance will be poor. Please report this to pgsql-bugs(at)postgresql(dot)org(dot)
>
> Hi Richard,
>
> What's a RISC-V, and can you provide some gcc assembler implementing
> spinlocks for it? See commentary and code for other platforms in
> src/include/storage/s_lock.h.

The answer to the first question is a lot easier than the second :-)

RISC-V is an open source instruction set architecture. https://riscv.org/
I'm currently compiling Fedora for RISC-V and this was the thing
that stops PostgreSQL from being compiled.
https://fedoraproject.org/wiki/Architectures/RISC-V

I looked at the file you pointed to. I believe it should be possible
to follow the ARM implementation and call __sync_lock_test_and_set (a
GCC builtin). I will try this out, but note that compiling anything
on RISC-V by hand is currently a very tedious process that can take
many hours.

- - -

Yesterday I added --disable-spinlocks and built PostgreSQL again
overnight, and it compiles fine but fails in the tests:

https://fedorapeople.org/groups/risc-v/logs/postgresql/9.5.5-1.fc25.0.riscv64/build.log

The errors mostly seem to be:

ERROR: unexpected EOF on client connection with an open transaction

This is *probably* because our kernel lacks networking support, but
I didn't look at this in great detail yet.

Rich.

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