This patch series intends to enable MSG_ZEROCOPY in QIOChannel, and make
use of it for multifd migration performance improvement.
Patch #1 creates new callbacks for QIOChannel, allowing the implementation
of asynchronous writing.
Patch #2 implements async_write and async_flush on QIOChannelSocket,
Patch #3 Makes use of async_write + async_flush to enable MSG_ZEROCOPY
for migration using multifd nocomp.
Results:
So far, the resource usage of __sys_sendmsg() reduced 15 times, and the
overall migration took 13-18% less time, based in synthetic workload.
The objective is to reduce migration time in hosts with heavy cpu usage.
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Changes since v1:
- Reimplemented the patchset using async_write + async_flush approach.
- Implemented a flush to be able to tell whenever all data was written.
Leonardo Bras (3):
QIOCHannel: Add io_async_writev & io_async_flush callbacks
QIOChannelSocket: Implement io_async_write & io_async_flush
multifd: Send using asynchronous write on nocomp to send RAM pages.
include/io/channel-socket.h | 2 +
include/io/channel.h | 93 +++++++++++++++++++----
io/channel-socket.c | 145 ++++++++++++++++++++++++++++++++++--
io/channel.c | 66 ++++++++++++----
migration/multifd.c | 3 +-
5 files changed, 271 insertions(+), 38 deletions(-)
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2.33.0