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Re: [PATCH 2/4] migration: check for rate_limit_max for RATE_LIMIT_DISAB
From: |
Fabiano Rosas |
Subject: |
Re: [PATCH 2/4] migration: check for rate_limit_max for RATE_LIMIT_DISABLED |
Date: |
Fri, 22 Sep 2023 14:38:04 -0300 |
Elena Ufimtseva <elena.ufimtseva@oracle.com> writes:
> In migration rate limiting atomic operations are used
> to read the rate limit variables and transferred bytes and
> they are expensive. Check first if rate_limit_max is equal
> to RATE_LIMIT_DISABLED and return false immediately if so.
>
> Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
> ---
> migration/migration-stats.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/migration/migration-stats.c b/migration/migration-stats.c
> index 095d6d75bb..abc31483d5 100644
> --- a/migration/migration-stats.c
> +++ b/migration/migration-stats.c
> @@ -24,14 +24,14 @@ bool migration_rate_exceeded(QEMUFile *f)
> return true;
> }
>
> - uint64_t rate_limit_start = stat64_get(&mig_stats.rate_limit_start);
> - uint64_t rate_limit_current = migration_transferred_bytes(f);
There's a qemu_fflush() hiding inside migration_transferred_bytes(). It
currently always flushes if we haven't detected an error in the
file. After this patch we will stop flushing at this point if
ratelimiting is disabled.
You might want to add that information to the commit message to make it
easier to track if this ends up causing a regression.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
- [PATCH 0/4] multifd: various fixes, Elena Ufimtseva, 2023/09/22
- [PATCH 1/4] multifd: wait for channels_ready before sending sync, Elena Ufimtseva, 2023/09/22
- [PATCH 3/4] multifd: fix counters in multifd_send_thread, Elena Ufimtseva, 2023/09/22
- [PATCH 4/4] multifd: reset next_packet_len after sending pages, Elena Ufimtseva, 2023/09/22
- [PATCH 2/4] migration: check for rate_limit_max for RATE_LIMIT_DISABLED, Elena Ufimtseva, 2023/09/22
- Re: [PATCH 2/4] migration: check for rate_limit_max for RATE_LIMIT_DISABLED,
Fabiano Rosas <=
- Re: [PATCH 0/4] multifd: various fixes, Fabiano Rosas, 2023/09/22