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Re: [Qemu-devel] [PATCH v9 10/12] migration: Transfer pages over new cha
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v9 10/12] migration: Transfer pages over new channels |
Date: |
Tue, 17 Oct 2017 15:18:55 +0100 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
* Juan Quintela (address@hidden) wrote:
> We switch for sending the page number to send real pages.
>
> Signed-off-by: Juan Quintela <address@hidden>
I think this is OK if squashed with the 'test' patch to remove
the test stuff.
Some minor comments below.
> --
>
> Remove the HACK bit, now we have the function that calculates the size
> of a page exported.
> Rename multifd_pages{_now}, to sent pages
> Remove multifd pages field, it is the same than normal pages
> ---
> migration/migration.c | 7 ++++++-
> migration/ram.c | 39 +++++++++++----------------------------
> 2 files changed, 17 insertions(+), 29 deletions(-)
>
> diff --git a/migration/migration.c b/migration/migration.c
> index 54ef095d82..1bd87a4e44 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -2085,6 +2085,7 @@ static void *migration_thread(void *opaque)
> */
> int64_t threshold_size = 0;
> int64_t qemu_file_bytes = 0;
> + int64_t sent_pages = 0;
> int64_t start_time = initial_time;
> int64_t end_time;
> bool old_vm_running = false;
> @@ -2173,8 +2174,11 @@ static void *migration_thread(void *opaque)
> current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
> if (current_time >= initial_time + BUFFER_DELAY) {
> uint64_t qemu_file_bytes_now = qemu_ftell(s->to_dst_file);
> + uint64_t sent_pages_now = ram_counters.normal;
> uint64_t transferred_bytes =
> - qemu_file_bytes_now - qemu_file_bytes;
> + (qemu_file_bytes_now - qemu_file_bytes) +
> + (sent_pages_now - sent_pages) *
> + qemu_target_page_size();
This could do with commenting to explain the difference between the
two sets of counts.
> uint64_t time_spent = current_time - initial_time;
> double bandwidth = (double)transferred_bytes / time_spent;
> threshold_size = bandwidth * s->parameters.downtime_limit;
> @@ -2194,6 +2198,7 @@ static void *migration_thread(void *opaque)
> qemu_file_reset_rate_limit(s->to_dst_file);
> initial_time = current_time;
> qemu_file_bytes = qemu_file_bytes_now;
> + sent_pages = sent_pages_now;
> }
> if (qemu_file_rate_limit(s->to_dst_file)) {
> /* usleep expects microseconds */
> diff --git a/migration/ram.c b/migration/ram.c
> index 4c16d0775b..981f345294 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -494,21 +494,15 @@ static void *multifd_send_thread(void *opaque)
> if (p->pages.num) {
> Error *local_err = NULL;
> size_t ret;
> - int i;
> int num;
>
> num = p->pages.num;
> p->pages.num = 0;
> qemu_mutex_unlock(&p->mutex);
> -
> - for (i = 0; i < num; i++) {
> - ret = qio_channel_write_all(p->c,
> - (const char *)&p->pages.iov[i].iov_base,
> - sizeof(uint8_t *), &local_err);
> - if (ret != 0) {
> - terminate_multifd_send_threads(local_err);
> - return NULL;
> - }
> + ret = qio_channel_writev_all(p->c, p->pages.iov, num,
> &local_err);
> + if (ret != 0) {
> + terminate_multifd_send_threads(local_err);
> + return NULL;
> }
> qemu_mutex_lock(&multifd_send_state->mutex);
> p->done = true;
> @@ -691,7 +685,6 @@ int multifd_load_cleanup(Error **errp)
> static void *multifd_recv_thread(void *opaque)
> {
> MultiFDRecvParams *p = opaque;
> - uint8_t *recv_address;
>
> qemu_sem_post(&p->ready);
> while (true) {
> @@ -703,27 +696,16 @@ static void *multifd_recv_thread(void *opaque)
> if (p->pages.num) {
> Error *local_err = NULL;
> size_t ret;
> - int i;
> int num;
>
> num = p->pages.num;
> p->pages.num = 0;
>
> - for (i = 0; i < num; i++) {
> - ret = qio_channel_read_all(p->c, (char *)&recv_address,
> - sizeof(uint8_t *), &local_err);
> - if (ret != 0) {
> - terminate_multifd_recv_threads(local_err);
> - return NULL;
> - }
> - if (recv_address != p->pages.iov[i].iov_base) {
> - error_setg(&local_err, "received %p and expecting %p
> (%d)",
> - recv_address, p->pages.iov[i].iov_base, i);
> - terminate_multifd_recv_threads(local_err);
> - return NULL;
> - }
> + ret = qio_channel_readv_all(p->c, p->pages.iov, num, &local_err);
> + if (ret != 0) {
> + terminate_multifd_recv_threads(local_err);
> + return NULL;
> }
A trace or two in each of these threads would probably help understand
what's going on.
> -
> p->done = true;
> qemu_mutex_unlock(&p->mutex);
> qemu_sem_post(&p->ready);
> @@ -1288,8 +1270,10 @@ static int ram_multifd_page(RAMState *rs,
> PageSearchStatus *pss,
> offset | RAM_SAVE_FLAG_MULTIFD_PAGE);
> fd_num = multifd_send_page(p, rs->migration_dirty_pages == 1);
> qemu_put_be16(rs->f, fd_num);
> + if (fd_num != MULTIFD_CONTINUE) {
> + qemu_fflush(rs->f);
> + }
Could do with a comment.
Dave
> ram_counters.transferred += 2; /* size of fd_num */
> - qemu_put_buffer(rs->f, p, TARGET_PAGE_SIZE);
> ram_counters.transferred += TARGET_PAGE_SIZE;
> pages = 1;
> ram_counters.normal++;
> @@ -3155,7 +3139,6 @@ static int ram_load(QEMUFile *f, void *opaque, int
> version_id)
> case RAM_SAVE_FLAG_MULTIFD_PAGE:
> fd_num = qemu_get_be16(f);
> multifd_recv_page(host, fd_num);
> - qemu_get_buffer(f, host, TARGET_PAGE_SIZE);
> break;
>
> case RAM_SAVE_FLAG_EOS:
> --
> 2.13.5
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- Re: [Qemu-devel] [PATCH v9 07/12] migration: Create thread infrastructure for multifd recv side, (continued)
- [Qemu-devel] [PATCH v9 08/12] migration: Test new fd infrastructure, Juan Quintela, 2017/10/04
- [Qemu-devel] [PATCH v9 05/12] migration: Create ram_multifd_page, Juan Quintela, 2017/10/04
- [Qemu-devel] [PATCH v9 09/12] migration: Rename initial_bytes, Juan Quintela, 2017/10/04
- [Qemu-devel] [PATCH v9 11/12] migration: Flush receive queue, Juan Quintela, 2017/10/04
- [Qemu-devel] [PATCH v9 10/12] migration: Transfer pages over new channels, Juan Quintela, 2017/10/04
- Re: [Qemu-devel] [PATCH v9 10/12] migration: Transfer pages over new channels,
Dr. David Alan Gilbert <=
- [Qemu-devel] [PATCH v9 12/12] migration: Add multifd test, Juan Quintela, 2017/10/04