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| author | Hyman Huang <yong.huang@smartx.com> | 2024-10-17 14:42:52 +0800 |
|---|---|---|
| committer | Peter Xu <peterx@redhat.com> | 2024-10-31 15:48:18 -0400 |
| commit | d481cec75658b313be3ae8fea3f800780e5c937b (patch) | |
| tree | a6b4fc5478a8a8bec6e7ec69cdd8f64b444e24fe /migration/cpu-throttle.c | |
| parent | 054e5d66e53e48f842c1cce61dc1b714fe9bf0ee (diff) | |
| download | qemu-d481cec75658b313be3ae8fea3f800780e5c937b.zip qemu-d481cec75658b313be3ae8fea3f800780e5c937b.tar.gz qemu-d481cec75658b313be3ae8fea3f800780e5c937b.tar.bz2 | |
migration: Move cpu-throttle.c from system to migration
Move cpu-throttle.c from system to migration since it's
only used for migration; this makes us avoid exporting the
util functions and variables in misc.h but export them in
migration.h when implementing the periodic ramblock dirty
sync feature in the upcoming commits.
Since CPU throttle timers are only used in migration, move
their registry to migration_object_init.
Signed-off-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/c1b3efaa0cb49e03d422e9da97bdb65cc3d234d1.1729146786.git.yong.huang@smartx.com
[peterx: Fix build on MacOS on cocoa.m, not move cpu-throttle.h yet]
[peterx: Fix subject spelling, per pm215]
Signed-off-by: Peter Xu <peterx@redhat.com>
Diffstat (limited to 'migration/cpu-throttle.c')
| -rw-r--r-- | migration/cpu-throttle.c | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/migration/cpu-throttle.c b/migration/cpu-throttle.c new file mode 100644 index 0000000..7632dc6 --- /dev/null +++ b/migration/cpu-throttle.c @@ -0,0 +1,131 @@ +/* + * QEMU System Emulator + * + * Copyright (c) 2003-2008 Fabrice Bellard + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "qemu/osdep.h" +#include "qemu/thread.h" +#include "hw/core/cpu.h" +#include "qemu/main-loop.h" +#include "sysemu/cpus.h" +#include "sysemu/cpu-throttle.h" +#include "trace.h" + +/* vcpu throttling controls */ +static QEMUTimer *throttle_timer; +static unsigned int throttle_percentage; + +#define CPU_THROTTLE_PCT_MIN 1 +#define CPU_THROTTLE_PCT_MAX 99 +#define CPU_THROTTLE_TIMESLICE_NS 10000000 + +static void cpu_throttle_thread(CPUState *cpu, run_on_cpu_data opaque) +{ + double pct; + double throttle_ratio; + int64_t sleeptime_ns, endtime_ns; + + if (!cpu_throttle_get_percentage()) { + return; + } + + pct = (double)cpu_throttle_get_percentage() / 100; + throttle_ratio = pct / (1 - pct); + /* Add 1ns to fix double's rounding error (like 0.9999999...) */ + sleeptime_ns = (int64_t)(throttle_ratio * CPU_THROTTLE_TIMESLICE_NS + 1); + endtime_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + sleeptime_ns; + while (sleeptime_ns > 0 && !cpu->stop) { + if (sleeptime_ns > SCALE_MS) { + qemu_cond_timedwait_bql(cpu->halt_cond, + sleeptime_ns / SCALE_MS); + } else { + bql_unlock(); + g_usleep(sleeptime_ns / SCALE_US); + bql_lock(); + } + sleeptime_ns = endtime_ns - qemu_clock_get_ns(QEMU_CLOCK_REALTIME); + } + qatomic_set(&cpu->throttle_thread_scheduled, 0); +} + +static void cpu_throttle_timer_tick(void *opaque) +{ + CPUState *cpu; + double pct; + + /* Stop the timer if needed */ + if (!cpu_throttle_get_percentage()) { + return; + } + CPU_FOREACH(cpu) { + if (!qatomic_xchg(&cpu->throttle_thread_scheduled, 1)) { + async_run_on_cpu(cpu, cpu_throttle_thread, + RUN_ON_CPU_NULL); + } + } + + pct = (double)cpu_throttle_get_percentage() / 100; + timer_mod(throttle_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT) + + CPU_THROTTLE_TIMESLICE_NS / (1 - pct)); +} + +void cpu_throttle_set(int new_throttle_pct) +{ + /* + * boolean to store whether throttle is already active or not, + * before modifying throttle_percentage + */ + bool throttle_active = cpu_throttle_active(); + + trace_cpu_throttle_set(new_throttle_pct); + + /* Ensure throttle percentage is within valid range */ + new_throttle_pct = MIN(new_throttle_pct, CPU_THROTTLE_PCT_MAX); + new_throttle_pct = MAX(new_throttle_pct, CPU_THROTTLE_PCT_MIN); + + qatomic_set(&throttle_percentage, new_throttle_pct); + + if (!throttle_active) { + cpu_throttle_timer_tick(NULL); + } +} + +void cpu_throttle_stop(void) +{ + qatomic_set(&throttle_percentage, 0); +} + +bool cpu_throttle_active(void) +{ + return (cpu_throttle_get_percentage() != 0); +} + +int cpu_throttle_get_percentage(void) +{ + return qatomic_read(&throttle_percentage); +} + +void cpu_throttle_init(void) +{ + throttle_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL_RT, + cpu_throttle_timer_tick, NULL); +} |