Before the collection goroutine wakes up every 1 second (as configured).
This sleep interval is in case there are no stats to collect we don't
end up in a tight loop.
Instead use a condition variable to signal that a collection is needed.
This prevents us from waking the goroutine needlessly when there is no
one looking for stats.
For now I've kept the sleep just moved it to the end of the loop, which
gives some space between collections.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
(cherry picked from commit e75e6b0e31)
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Commit fd0e24b718 changed
the stats collection loop to use a `sleep()` instead
of `time.Tick()` in the for-loop.
This change caused a regression in situations where
no stats are being collected, or an error is hit
in the loop (in which case the loop would `continue`,
and the `sleep()` is not hit).
This patch puts the sleep at the start of the loop
to guarantee it's always hit.
This will delay the sampling, which is similar to the
behavior before fd0e24b718.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
To avoid noise in sampling CPU usage metrics, we now sample the system
usage closer to the actual response from the underlying runtime. Because
the response from the runtime may be delayed, this makes the sampling
more resilient in loaded conditions. In addition to this, we also
replace the tick with a sleep to avoid situations where ticks can backup
under loaded conditions.
The trade off here is slightly more load reading the system CPU usage
for each container. There may be an optimization required for large
amounts of containers but the cost is on the order of 15 ms per 1000
containers. If this becomes a problem, we can time slot the sampling,
but the complexity may not be worth it unless we can test further.
Unfortunately, there aren't really any good tests for this condition.
Triggering this behavior is highly system dependent. As a matter of
course, we should qualify the fix with the users that are affected.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
While a `types.go` file is handly when there are a lot of record types,
it is completely obnoxious when used for concrete, utility types with a
struct, new function and method set in the same file. This change
removes the `types.go` file in favor of the simpler approach.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Files that are suffixed with `_linux.go` or `_windows.go` are
already only built on Linux / Windows, so these build-tags
were redundant.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Use strongly typed errors to set HTTP status codes.
Error interfaces are defined in the api/errors package and errors
returned from controllers are checked against these interfaces.
Errors can be wraeped in a pkg/errors.Causer, as long as somewhere in the
line of causes one of the interfaces is implemented. The special error
interfaces take precedence over Causer, meaning if both Causer and one
of the new error interfaces are implemented, the Causer is not
traversed.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
If we get "container not found" error from containerd, it's possibly
because that this container has already been stopped. It will be ok to
ignore this error and just return an empty stats.
Signed-off-by: Yuanhong Peng <pengyuanhong@huawei.com>
Treat return code -1 as error instead.
People from glibc say that errno is undefined in case of successful
sysconf call according to POSIX standard:
Glibc bug: https://sourceware.org/bugzilla/show_bug.cgi?id=21536
More over in sysconf man it is wrongly said that "errno is not changed"
on success. So I've created a bug to man-pages:
https://bugzilla.kernel.org/show_bug.cgi?id=195955
Background: Glibc's sysconf(_SC_NPROCESSORS_ONLN) changes errno to
ENOENT, if there is no /sys/devices/system/cpu/online file, while
the call itself is successful. In Virtuozzo containers we prohibit
most of sysfs files for security reasons. So we have Run():daemon
/stats/collector.go infinitely loop never actualy collecting stats
from publisher pairs.
v2: add comment
Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
In https://github.com/torvalds/linux/commit/5ca3726 (released in v4.7-rc1) the
content of the `cpuacct.usage_percpu` file in sysfs was changed to include both
online and offline cpus. This broke the arithmetic in the stats helpers used by
`docker stats`, since it was using the length of the PerCPUUsage array as a
proxy for the number of online CPUs.
Add current number of online CPUs to types.StatsJSON and use it in the
calculation.
Keep a fallback to `len(v.CPUStats.CPUUsage.PercpuUsage)` so this code
continues to work when talking to an older daemon. An old client talking to a
new daemon will ignore the new field and behave as before.
Fixes#28941.
Signed-off-by: Ian Campbell <ian.campbell@docker.com>
When `docker stats` stopped containers, client will get empty stats data,
this commit will gurantee client always get "Name" and "ID" field, so
that it can format with `ID` and `Name` fields successfully.
Signed-off-by: Zhang Wei <zhangwei555@huawei.com>
