Part of the API discovery cache uses an HTTP RoundTripper that
transparently caches responses to disk. The upstream implementation of
the disk cache is hard coded to call Sync() on every file it writes.
This has noticably poor performance on modern Macs, which ask their disk
controllers to flush all the way to persistant storage because Go uses
the `F_FULLFSYNC` fnctl. Apple recommends minimizing this behaviour in
order to avoid degrading performance and increasing disk wear.
The content of the discovery cache is not critical; it is indeed just a
cache and can be recreated by hitting the API servers' discovery
endpoints. This commit replaces upstream httpcache's diskcache
implementation with a similar implementation that can use CRC-32
checksums to detect corrupted cache entries at read-time. When such an
entry is detected (e.g. because it was only partially flushed to
permanent storage before the host lost power) the cache will report a
miss. This causes httpcache to fall back to its underlying HTTP
transport (i.e. the real API server) and re-cache the resulting value.
Apart from adding CRC-32 checksums and avoiding calling fsync this
implementation differs from upstream httpcache's diskcache package in
that it uses FNV-32a hashes rather than MD5 hashes of cache keys in
order to generate filenames.
Signed-off-by: Nic Cope <nicc@rk0n.org>
Kubernetes-commit: 7a2c6a432f9e8db8b84abe5607843429f8bff417
This benchmark is intended to demonstrate a performance improvement
gained by removing fsyncs. Refer to the below issue for more detail.
https://github.com/kubernetes/kubernetes/issues/110753
Signed-off-by: Nic Cope <nicc@rk0n.org>
Kubernetes-commit: eace46906512b99c23ad9635edc2ea055363a602
This makes ktesting more resilient against logging from leaked goroutines,
which is a problem that came up in kubelet node shutdown
tests (https://github.com/kubernetes/kubernetes/issues/110854).
Kubernetes-commit: 3581e308835c69b11b2c9437db44073129e0e2bf
This will help us to get rid of `Ginkgo` v1 dep.
Signed-off-by: Dave Chen <dave.chen@arm.com>
Kubernetes-commit: 597071af17377f5ab4de03804b0d8b41f73fe7ce
The main practical advantage is that klog.Fatal no longer dumps the backtrace
of all goroutines.
Kubernetes-commit: f05e327ca611c23469ef41310d1d59b384cedc27
To be able to implement controllers that are dynamically deciding
on which resources to watch, it is required to get rid of
dedicated watches and event handlers again. This requires the
possibility to remove event handlers from SharedIndexInformers again.
Stopping an informer is not sufficient, because there might
be multiple controllers in a controller manager that independently
decide which resources to watch.
Unfortunately the ResourceEventHandler interface encourages to use
value objects for handlers (like the ResourceEventHandlerFuncs
struct, that uses value receivers to implement the interface).
Go does not support comparison of function pointers and therefore
the comparison of such structs is not possible, also. To be able
to remove all kinds of handlers and to solve the problem of
multi-registrations of handlers a registration handle is introduced.
It is returned when adding a handler and can later be used to remove
the registration again. This handle directly stores the created
listener to simplify the deletion.
Kubernetes-commit: 7436af3302088c979b431856c432b95dd230f847
