[v2,0/3] High downtime with 95+ throttle pct

Message

Yury Kotov July 16, 2019, 2:54 p.m. UTC

Hi,

V2:
* Added a test
* Fixed qemu_cond_timedwait for qsp

I wrote a test for migration auto converge and found out a strange thing:
1. Enable auto converge
2. Set max-bandwidth 1Gb/s
3. Set downtime-limit 1ms
4. Run standard test (just writes a byte per page)
5. Wait for converge
6. It's converged with 99% throttle percentage
7. The result downtime was about 300-600ms   <<<<

It's much higher than expected 1ms. I figured out that cpu_throttle_thread()
function sleeps for 100ms+ for high throttle percentage (>=95%) in VCPU thread.
And it sleeps even after a cpu kick.

I tried to fix it by using timedwait for ms part of sleep.
E.g timedwait(halt_cond, 1ms) + usleep(500).

Regards,
Yury

Yury Kotov (3):
  qemu-thread: Add qemu_cond_timedwait
  cpus: Fix throttling during vm_stop
  tests/migration: Add a test for auto converge

 cpus.c                   |  27 ++++++---
 include/qemu/thread.h    |  18 ++++++
 tests/migration-test.c   | 119 +++++++++++++++++++++++++++++++++++----
 util/qemu-thread-posix.c |  40 +++++++++----
 util/qemu-thread-win32.c |  16 ++++++
 util/qsp.c               |  18 ++++++
 6 files changed, 207 insertions(+), 31 deletions(-)

Comments

[e-mail] July 17, 2019, 1:25 p.m. UTC | #1

Patchew URL: https://patchew.org/QEMU/[e-mail]/



Hi,

This series failed the asan build test. Please find the testing commands and
their output below. If you have Docker installed, you can probably reproduce it
locally.

=== TEST SCRIPT BEGIN ===
#!/bin/bash
make docker-image-fedora V=1 NETWORK=1
time make docker-test-debug@fedora TARGET_LIST=x86_64-softmmu J=14 NETWORK=1
=== TEST SCRIPT END ===

clang -iquote /tmp/qemu-test/build/tests/libqos -iquote tests/libqos -iquote /tmp/qemu-test/src/tcg -iquote /tmp/qemu-test/src/tcg/i386 -I/tmp/qemu-test/src/linux-headers -I/tmp/qemu-test/build/linux-headers -iquote . -iquote /tmp/qemu-test/src -iquote /tmp/qemu-test/src/accel/tcg -iquote /tmp/qemu-test/src/include -I/usr/include/pixman-1  -I/tmp/qemu-test/src/dtc/libfdt -Werror  -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include  -fPIE -DPIE -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -std=gnu99  -Wno-string-plus-int -Wno-typedef-redefinition -Wno-initializer-overrides -Wexpansion-to-defined -Wendif-labels -Wno-shift-negative-value -Wno-missing-include-dirs -Wempty-body -Wnested-externs -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wold-style-definition -Wtype-limits -fstack-protector-strong  -I/usr/include/p11-kit-1     -I/usr/include/libpng16  -I/usr/include/spice-1 -I/usr/include/spice-server -I/usr/include/cacard -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/nss3 -I/usr/include/nspr4 -pthread -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/uuid -I/usr/include/pixman-1   -I/tmp/qemu-test/src/tests -MMD -MP -MT tests/libqos/virtio-serial.o -MF tests/libqos/virtio-serial.d -fsanitize=undefined -fsanitize=address -g   -c -o tests/libqos/virtio-serial.o /tmp/qemu-test/src/tests/libqos/virtio-serial.c
clang -iquote /tmp/qemu-test/build/tests/libqos -iquote tests/libqos -iquote /tmp/qemu-test/src/tcg -iquote /tmp/qemu-test/src/tcg/i386 -I/tmp/qemu-test/src/linux-headers -I/tmp/qemu-test/build/linux-headers -iquote . -iquote /tmp/qemu-test/src -iquote /tmp/qemu-test/src/accel/tcg -iquote /tmp/qemu-test/src/include -I/usr/include/pixman-1  -I/tmp/qemu-test/src/dtc/libfdt -Werror  -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include  -fPIE -DPIE -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -std=gnu99  -Wno-string-plus-int -Wno-typedef-redefinition -Wno-initializer-overrides -Wexpansion-to-defined -Wendif-labels -Wno-shift-negative-value -Wno-missing-include-dirs -Wempty-body -Wnested-externs -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wold-style-definition -Wtype-limits -fstack-protector-strong  -I/usr/include/p11-kit-1     -I/usr/include/libpng16  -I/usr/include/spice-1 -I/usr/include/spice-server -I/usr/include/cacard -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/nss3 -I/usr/include/nspr4 -pthread -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/uuid -I/usr/include/pixman-1   -I/tmp/qemu-test/src/tests -MMD -MP -MT tests/libqos/aarch64-xlnx-zcu102-machine.o -MF tests/libqos/aarch64-xlnx-zcu102-machine.d -fsanitize=undefined -fsanitize=address -g   -c -o tests/libqos/aarch64-xlnx-zcu102-machine.o /tmp/qemu-test/src/tests/libqos/aarch64-xlnx-zcu102-machine.c
clang -iquote /tmp/qemu-test/build/. -iquote . -iquote /tmp/qemu-test/src/tcg -iquote /tmp/qemu-test/src/tcg/i386 -I/tmp/qemu-test/src/linux-headers -I/tmp/qemu-test/build/linux-headers -iquote . -iquote /tmp/qemu-test/src -iquote /tmp/qemu-test/src/accel/tcg -iquote /tmp/qemu-test/src/include -I/tmp/qemu-test/src/tests/fp -I/tmp/qemu-test/src/tests/fp/berkeley-softfloat-3/source/include -I/tmp/qemu-test/src/tests/fp/berkeley-softfloat-3/source/8086-SSE -I/tmp/qemu-test/src/tests/fp/berkeley-testfloat-3/source -I/usr/include/pixman-1 -I/tmp/qemu-test/src/dtc/libfdt -Werror -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -fPIE -DPIE -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -std=gnu99 -Wno-string-plus-int -Wno-typedef-redefinition -Wno-initializer-overrides -Wexpansion-to-defined -Wendif-labels -Wno-shift-negative-value -Wno-missing-include-dirs -Wempty-body -Wnested-externs -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wold-style-definition -Wtype-limits -fstack-protector-strong -I/usr/include/p11-kit-1 -I/usr/include/libpng16 -I/usr/include/spice-1 -I/usr/include/spice-server -I/usr/include/cacard -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/nss3 -I/usr/include/nspr4 -pthread -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/uuid -I/usr/include/pixman-1 -DHW_POISON_H -DTARGET_ARM  -DSOFTFLOAT_ROUND_ODD -DINLINE_LEVEL=5 -DSOFTFLOAT_FAST_DIV32TO16 -DSOFTFLOAT_FAST_DIV64TO32 -DSOFTFLOAT_FAST_INT64  -DFLOAT16 -DFLOAT64 -DEXTFLOAT80 -DFLOAT128 -DFLOAT_ROUND_ODD -DLONG_DOUBLE_IS_EXTFLOAT80  -Wno-strict-prototypes -Wno-unknown-pragmas -Wno-uninitialized -Wno-missing-prototypes -Wno-return-type -Wno-unused-function -Wno-error -MMD -MP -MT test_a_extF80_z_f128.o -MF ./test_a_extF80_z_f128.d -fsanitize=undefined -fsanitize=address -g   -c -o test_a_extF80_z_f128.o /tmp/qemu-test/src/tests/fp/berkeley-testfloat-3/source/test_a_extF80_z_f128.c
/tmp/qemu-test/src/tests/migration-test.c:1163:5: error: implicit declaration of function 'migrate_set_parameter' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
    migrate_set_parameter(from, "cpu-throttle-initial", expected_pcts[1]);
    ^
/tmp/qemu-test/src/tests/migration-test.c:1163:5: note: did you mean 'migrate_set_parameter_int'?
/tmp/qemu-test/src/tests/migration-test.c:435:13: note: 'migrate_set_parameter_int' declared here
static void migrate_set_parameter_int(QTestState *who, const char *parameter,
            ^
/tmp/qemu-test/src/tests/migration-test.c:1163:5: error: this function declaration is not a prototype [-Werror,-Wstrict-prototypes]
    migrate_set_parameter(from, "cpu-throttle-initial", expected_pcts[1]);
    ^
2 errors generated.


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