Closed Bug 1254618 Opened 6 years ago Closed 6 years ago

modify nsTransactionStack to use nsDeque rather than std::deque

Categories

(Core :: DOM: Editor, defect)

defect
Not set
normal

Tracking

()

RESOLVED FIXED
mozilla48
Tracking Status
firefox48 --- fixed

People

(Reporter: froydnj, Assigned: froydnj)

Details

Attachments

(1 file)

Using std::deque here causes problems for libc++ builds; TestTXMgr on
OSX 10.6 opt times out when libc++'d std::deque is used.  Running the
test locally shows that the test process consumes gigabytes (!) of
memory and is thus reduced to swapping, rather than making any progress.
libc++'s std::deque also appears to be slightly slower in said test that
even OSX libstdc++'s std::deque.  (Admittedly, this test is artificial.)

Let's sidestep the slowness of libc++'s std::deque by rewriting
nsTransactionStack to use nsDeque rather than std::deque.  Not only does
this change enable OSX 10.6 tests to pass, it also makes TestTXMgr
significantly faster in opt builds: TestTXMgr is anywhere from 25-60%
faster (depending on the platform) than when using std::deque from
libstdc++ or libc++.
This is a straightforward data structures change that I think anybody could
review, but flagging Ehsan for old times' sake in editor/ and because he may be
interested in the libc++ issues.  (No, I didn't thoroughly investigate what
libc++ is doing wrong here, but I will note that this issue of libc++'s
std::deque being bad turns up on OSX and Android both.)
Attachment #8727970 - Flags: review?(ehsan)
Attachment #8727970 - Flags: review?(ehsan) → review+
https://hg.mozilla.org/mozilla-central/rev/fe2bdf95d0fc
Status: NEW → RESOLVED
Closed: 6 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla48
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