Re: [PATCH v6 01/12] migration/dirtyrate: setup up query-dirtyrate framwork

From: Zheng Chuan <zhengchuan@huawei.com>
To: David Edmondson <david.edmondson@oracle.com>,
	<quintela@redhat.com>, <eblake@redhat.com>, <dgilbert@redhat.com>,
	<berrange@redhat.com>
Cc: alex.chen@huawei.com, ann.zhuangyanying@huawei.com,
	zhang.zhanghailiang@huawei.com, xiexiangyou@huawei.com,
	qemu-devel@nongnu.org
Subject: Re: [PATCH v6 01/12] migration/dirtyrate: setup up query-dirtyrate framwork
Date: Mon, 31 Aug 2020 19:07:58 +0800	[thread overview]
Message-ID: <110f5a93-6bc4-4079-8e69-31aac0e51ee6@huawei.com> (raw)
In-Reply-To: <m2lfhvci17.fsf@oracle.com>


On 2020/8/31 16:54, David Edmondson wrote:
> On Saturday, 2020-08-29 at 10:52:46 +08, Chuan Zheng wrote:
> 
>> Add get_dirtyrate_thread() functions to setup query-dirtyrate
>> framework.
>>
>> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
>> Signed-off-by: YanYing Zhuang <ann.zhuangyanying@huawei.com>
>> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> 
> Modulo the question below...
> 
> Reviewed-by: David Edmondson <david.edmondson@oracle.com>
> 
>> ---
>>  migration/dirtyrate.c | 38 ++++++++++++++++++++++++++++++++++++++
>>  migration/dirtyrate.h | 29 +++++++++++++++++++++++++++++
>>  migration/meson.build |  2 +-
>>  3 files changed, 68 insertions(+), 1 deletion(-)
>>  create mode 100644 migration/dirtyrate.c
>>  create mode 100644 migration/dirtyrate.h
>>
>> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
>> new file mode 100644
>> index 0000000..44d673a
>> --- /dev/null
>> +++ b/migration/dirtyrate.c
>> @@ -0,0 +1,38 @@
>> +/*
>> + * Dirtyrate implement code
>> + *
>> + * Copyright (c) 2017-2020 HUAWEI TECHNOLOGIES CO.,LTD.
> 
> Idle query, given that I'm not a lawyer, has this code really been
> around since 2017?
> 
We have evaluated dirty rate by simulating dirtylog as qemu migration does in our first
inside-version since 2017, but it hurts vm performace, and the hash method replaced
the old method recently.
I will consider to write in since 2020, because it is indeed just refactored recently:)

>> + *
>> + * Authors:
>> + *  Chuan Zheng <zhengchuan@huawei.com>
>> + *
>> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
>> + * See the COPYING file in the top-level directory.
>> + */
>> +
>> +#include "qemu/osdep.h"
>> +#include "qapi/error.h"
>> +#include "cpu.h"
>> +#include "qemu/config-file.h"
>> +#include "exec/memory.h"
>> +#include "exec/ramblock.h"
>> +#include "exec/target_page.h"
>> +#include "qemu/rcu_queue.h"
>> +#include "qapi/qapi-commands-migration.h"
>> +#include "migration.h"
>> +#include "dirtyrate.h"
>> +
>> +static void calculate_dirtyrate(struct DirtyRateConfig config)
>> +{
>> +    /* todo */
>> +    return;
>> +}
>> +
>> +void *get_dirtyrate_thread(void *arg)
>> +{
>> +    struct DirtyRateConfig config = *(struct DirtyRateConfig *)arg;
>> +
>> +    calculate_dirtyrate(config);
>> +
>> +    return NULL;
>> +}
>> diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
>> new file mode 100644
>> index 0000000..5be9714
>> --- /dev/null
>> +++ b/migration/dirtyrate.h
>> @@ -0,0 +1,29 @@
>> +/*
>> + *  Dirtyrate common functions
>> + *
>> + *  Copyright (c) 2020 HUAWEI TECHNOLOGIES CO., LTD.
>> + *
>> + *  Authors:
>> + *  Chuan Zheng <zhengchuan@huawei.com>
>> + *
>> + *  This work is licensed under the terms of the GNU GPL, version 2 or later.
>> + *  See the COPYING file in the top-level directory.
>> + */
>> +
>> +#ifndef QEMU_MIGRATION_DIRTYRATE_H
>> +#define QEMU_MIGRATION_DIRTYRATE_H
>> +
>> +/*
>> + * Sample 512 pages per GB as default.
>> + * TODO: Make it configurable.
>> + */
>> +#define DIRTYRATE_DEFAULT_SAMPLE_PAGES            512
>> +
>> +struct DirtyRateConfig {
>> +    uint64_t sample_pages_per_gigabytes; /* sample pages per GB */
>> +    int64_t sample_period_seconds; /* time duration between two sampling */
>> +};
>> +
>> +void *get_dirtyrate_thread(void *arg);
>> +#endif
>> +
>> diff --git a/migration/meson.build b/migration/meson.build
>> index ac8ff14..b5b71c8 100644
>> --- a/migration/meson.build
>> +++ b/migration/meson.build
>> @@ -37,4 +37,4 @@ softmmu_ss.add(when: ['CONFIG_RDMA', rdma], if_true: files('rdma.c'))
>>  softmmu_ss.add(when: 'CONFIG_LIVE_BLOCK_MIGRATION', if_true: files('block.c'))
>>  softmmu_ss.add(when: 'CONFIG_ZSTD', if_true: [files('multifd-zstd.c'), zstd])
>>  
>> -specific_ss.add(when: 'CONFIG_SOFTMMU', if_true: files('ram.c'))
>> +specific_ss.add(when: 'CONFIG_SOFTMMU', if_true: files('dirtyrate.c', 'ram.c'))
>> -- 
>> 1.8.3.1
> 
> dme.
>