Commit 0f1bdb6 ("threadpool: send signal only when queue is empty")
introduces a regression where work is not evenly distributed across
the thread pool because the work queue's condition variable is only
signalled when the queue is empty, even when there are waiting workers.
It doesn't turn into outright deadlock because there is always
at least one thread making forward progress but it does degrade
throughput, sometimes massively so.
Signalling whenever there are waiting workers fixes the throughput
issue while still keeping the number of uv_cond_signal() calls low,
which was the motivation for commit 0f1bdb6.
Fixes: https://github.com/libuv/libuv/pull/490
Fixes: https://github.com/libuv/libuv/issues/492
PR-URL: https://github.com/libuv/libuv/pull/493
Reviewed-By: Saúl Ibarra Corretgé <saghul@gmail.com>
With uv_replace_allocator, it's possible to override the default
memory allocator's malloc and free calls with functions of the user's
choosing. This allows libuv to interoperate with projects requiring a
custom memory allocator.
Internally, all calls to malloc and free have been replaced with
uv__malloc and uv__free, respectively. The uv__malloc and uv__free
functions call malloc and free unless they have been overridden by a
previous call to uv_replace_allocator.
As part of this change, the special aligned memory allocations
performed in src/win/fs-event.c have been replaced with standard
allocations. The 4-byte alignment being requested in this file was
unnecessary, since standard allocators already guarantee at least an
8-byte alignment.
PR-URL: https://github.com/libuv/libuv/pull/231
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Saúl Ibarra Corretgé <saghul@gmail.com>
If libuv is loaded as a DLL and is later unloaded deadlocks can happen
when running atexit handlers, so we can't use synchronization
priomitives or join threads there.
For reference see https://github.com/saghul/pyuv/issues/171
