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| author | Paolo Bonzini <pbonzini@redhat.com> | 2019-04-09 14:28:23 +0200 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2019-05-10 10:53:21 +0100 |
| commit | 993ed89f35bf2b2250727667f2a640b3c232259f (patch) | |
| tree | f53e1f9d206d95153bde411252cb2f23617fa919 /docs/qcow2-cache.txt | |
| parent | 118f99442d3a8ce47836978cddd9206ac2d2b001 (diff) | |
aio-posix: ensure poll mode is left when aio_notify is called
With aio=thread, adaptive polling makes latency worse rather than
better, because it delays the execution of the ThreadPool's
completion bottom half.
event_notifier_poll() does run while polling, detecting that
a bottom half was scheduled by a worker thread, but because
ctx->notifier is explicitly ignored in run_poll_handlers_once(),
scheduling the BH does not count as making progress and
run_poll_handlers() keeps running. Fix this by recomputing
the deadline after *timeout could have changed.
With this change, ThreadPool still cannot participate in polling
but at least it does not suffer from extra latency.
Reported-by: Sergio Lopez <slp@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20190409122823.12416-1-pbonzini@redhat.com
Cc: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-block@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1553692145-86728-1-git-send-email-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20190409122823.12416-1-pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'docs/qcow2-cache.txt')
0 files changed, 0 insertions, 0 deletions