The idea is to drain the socket and do a single RocksDB WAL
write/fsync for all the write requests we have found.
The read requests are immediately executed. The reasoning here is
that currently write requests are _a lot_ slower than the read
requests because fsyncing takes ~500us on fsf1. In the future this
might change.
Since we're at it, we also use batch UDP syscalls in the CDC.
Fixes#119.
The goal here is to not have constant wakeups due to timeout. Do
not attempt to clean things up nicely before termination -- just
terminate instead. We can setup a proper termination system in
the future, I first want to see if this makes a difference.
Also, change xmon to use pipes for communication, so that it can
wait without timers as well.
Also, `write` directly for logging, so that we know the logs will
make it to the file after the logging call returns (since we now
do not have the chance to flush them afterwards).
This is one of the two data model/protocol changes I want to perform
before going into production, the other being file atime.
Right now the kernel module does not take advantage of this, but
it's OK since I tested the rest of the code reasonably and the goal
here is to perform the protocol/data changes.
Initial version really by Pawel, but many changes in between.
Big outstanding issues:
* span cache reclamation (unbounded memory otherwise...)
* bad block service detection and workarounds
* corrupted blocks detection and workaround
Co-authored-by: Paweł Dziepak <pawel.dziepak@xtxmarkets.com>
The main thing that's added is full RS support, but a lot of things
were rejigged along the way. The tests are still a bit lacking,
and will be augmented in future commits.
It is currently very fragile, due to:
* Differing versions of compilers/DWARF version result in a variety
of breakages in the our code which analyzes the DWARF info;
* With musl, libunwind seems to be currently unable to traverse
beyond signal handlers, due to the DWARF information not
being present in the signal frame.
See <https://maskray.me/blog/2022-04-10-unwinding-through-signal-handler>.
Note that I have not verified that the problem in the blog
post above is indeed what we're hitting, but it seems plausible.
Also, produce fully static binaries. This means that `gethostname`
does not work (doesn't work with static glibc unless you build it
with `--enable-static-nss`, which no distro builds glibc with).
