09.11.2020 11:50, Vladimir Sementsov-Ogievskiy wrote:
06.11.2020 15:42, Andrey Shinkevich wrote:
The subject was discussed here:
https://lists.gnu.org/archive/html/qemu-devel/2017-05/msg00206.html
This series is a solution for the issue with QMP monitor buffered input.
A little parser is introduced to throttle JSON commands read from the
buffer so that QMP requests do not overwhelm the monitor input queue.
A side effect raised in the test #247 was managed in the first patch.
It may be considered as a workaround. Any sane fix suggested will be
appreciated.
Note:
This series goes after the Vladimir's one:
'[PATCH v3 00/25] backup performance: block_status + async"'
To make the test #129 passed, the following patch should be applied first:
'[PATCH v3 01/25] iotests: 129 don't check backup "busy"'.
Hi!
I tried the following test:
start qemu:
./qemu-system-x86_64 -qmp stdio
type the following in one line:
{ 'execute': 'qmp_capabilities' }{ 'execute': 'quit' }
press Enter.
Without your patches, the qemu quits immediately, printing double "{"return":
{}}".
With your patches applied qemu prints "{"return": {}}" only once and doesn't
quit, until I press Enter the second time.
Positive thing: the patches do increase performance:
for me, the following command:
(echo "{ 'execute': 'qmp_capabilities' }"; for i in {1..10000}; do echo "{ 'execute':
'query-block-jobs' }"; done; echo "{ 'execute': 'quit' }" ) | time ./qemu-system-x86_64 -qmp
stdio > /dev/null
shows 2.4s on master and 0.6s after patches
Andrey Shinkevich (2):
iotests: add another bash sleep command to 247
monitor: increase amount of data for monitor to read
chardev/char-fd.c | 64 +++++++++++++++++++++++++++++++++++++++++++++-
chardev/char-socket.c | 54 +++++++++++++++++++++++++++-----------
chardev/char.c | 40 +++++++++++++++++++++++++++++
include/chardev/char.h | 15 +++++++++++
monitor/monitor.c | 2 +-
tests/qemu-iotests/247 | 2 ++
tests/qemu-iotests/247.out | 1 +
7 files changed, 161 insertions(+), 17 deletions(-)
--
Best regards,
Vladimir
