Commit Graph

9 Commits

Author SHA1 Message Date
Willy Tarreau 03e7853581 BUILD: remove obsolete support for -mregparm / USE_REGPARM
This used to be a minor optimization on ix86 where registers are scarce
and the calling convention not very efficient, but this platform is not
relevant enough anymore to warrant all this dirt in the code for the sake
of saving 1 or 2% of performance. Modern platforms don't use this at all
since their calling convention already defaults to using several registers
so better get rid of this once for all.
2020-02-25 07:41:47 +01:00
Willy Tarreau 318d0c2055 BUG/MAJOR: ebtree/scope: properly tag upper nodes during insertion
Christopher found a case where some tasks would remain unseen in the run
queue and would spontaneously appear after certain apparently unrelated
operations performed by the other thread.

It's in fact the insertion which is not correct, the node serving as the
top of duplicate tree wasn't properly updated, just like the each top of
subtree in a duplicate tree. This had the effect that after some removals,
the incorrectly tagged node would hide the underlying ones, which would
then suddenly re-appear once they were removed.

This is 1.8-specific, no backport is needed.
2017-11-15 19:43:05 +01:00
Willy Tarreau cfaa6e7ef3 MINOR: ebtree/scope: simplify the lookup functions by using eb32sc_next_with_parent()
This gets rid of the nasty loop we used to have at the end of the lookup
function and instead falls back to the normal walk down code.
2017-11-13 19:34:09 +01:00
Willy Tarreau d19ec7d502 BUG/MAJOR: ebtree/scope: fix insertion and removal of duplicates in scope-aware trees
Commit ca30839 and following ("MINOR: ebtree: implement the scope-aware
functions for eb32") improperly dealt with the scope in duplicate trees.
The insertion was too lenient in that it would always mark the whole
rightmost chain below the insertion point, and the removal could leave
marks of non-existing scopes causing next()/first() to visit the wrong
branch and return NULL.

For insertion, we must only tag the nodes between the head of the dup
tree and the insertion point which is the top of the lowest subtree. For
removal, the new scope must be be calculated by oring the scopes of the
two new branches and is irrelevant to the previous values.

No backport is needed, this is purely 1.8-specific.
2017-11-13 19:34:09 +01:00
Willy Tarreau 8878b6c4cb MINOR: ebtree: implement eb32sc_lookup_ge_or_first()
In the scheduler we always have to loop back to the beginning after
we don't find the last entry, so let's implement this in a new lookup
function instead. The resulting code is slightly faster, mostly due
to the fact that there's much less inlined code in the fast path.
2017-11-06 11:20:11 +01:00
Willy Tarreau d1d55ac619 MEDIUM: ebtree: only consider the branches matching the scope in lookups
Now when looking up a node via eb32sc_first(), eb32sc_next(), and
eb32sc_lookup_ge(), we only focus on the branches matching the requested
scope. The code must be careful to miss no branch. It changes a little
bit from the previous one because the scope stored on the intermediary
nodes is not exact (since we don't propagate upwards during deletion),
so in case a lookup fails, we have to walk up and pick the next matching
entry.
2017-11-06 11:20:11 +01:00
Willy Tarreau ef8d0dcefd MINOR: ebtree: update the eb32sc parent node's scope on delete
During a delete operation, if the deleted node is above its leaf's
parent, this parent will replace the node and then go up. In this
case it is important to update the new parent's scope to reflect
the presence of other branches.

It's worth noting that in theory we should precisely recompute the
exact node value, but it seems that it's not worth it for the rare
cases there is a mismatch.
2017-11-06 11:20:11 +01:00
Willy Tarreau 5d19fd479a MEDIUM: ebtree: specify the scope of every node inserted via eb32sc
Here we mark each visited node with the scope bits of the node being
inserted. This will allow the lookup to skip certain non-interesting
nodes.
2017-11-06 11:20:11 +01:00
Willy Tarreau ca30839a85 MINOR: ebtree: implement the scope-aware functions for eb32
A new kind of tree nodes is currently being developed in ebtree v7,
consisting in storing a scope in each node indicating a visibility
mask so that certain nodes are not reported on certain lookups. The
initial goal was to make this usable with a multi-thread scheduler.

Since the ebtree v7 code is completely different from v6, this patch
instead copies the minimally required functions from eb32 and ebtree
and calls them "eb32sc_*". At the moment the scope is not implemented,
it's only passed in arguments.
2017-11-06 11:20:11 +01:00