checkpoint image compression (compressio) implies additional overhead
during its operations. when gvisor restores the kernel state inflate()
algorithm requires:
- CPU to un/compress the data
- Memory blocks to store and un/compress data
memory blocks originate from the bytes.Buffers and the sync.Pool that
tries to reuse them. they are released only when the system decides it
is a good moment:
pool.go: runtime_registerPoolCleanup(poolCleanup)
in my system (and in production) it takes around 240s to get the related
memory region freed (unmapped()).
during that period of time from the image state is read and the kernel is
loaded till the moment when the `poolCleanup` is called + GC() releasing
buffers gVisor Kernel (sandbox) process holds tens and hundreds of
megabytes of anonymous memory pages (RAM) busy (allocated+reserved).
pretty much often, the memory overhead of using compression can result in x2
memory overhead in production system with checkpoints restore and +100ms
(hundreds) ms of startup latency just to uncompress the image.
our use case does not suffer from having uncompressed images on disk but
suffer from the waste of memory during startup and CPU overhead.
this patch adds flag to disable compression for containers checkpoints.
Signed-off-by: Ivan Prisyazhnyy <[email protected]>
Previously, it was not possible to encode/decode an object graph which
contained a pointer to a field within another type. This was because the
encoder was previously unable to disambiguate a pointer to an object and a
pointer within the object.
This CL remedies this by constructing an address map tracking the full memory
range object occupy. The encoded Refvalue message has been extended to allow
references to children objects within another object. Because the encoding
process may learn about object structure over time, we cannot encode any
objects under the entire graph has been generated.
This CL also updates the state package to use standard interfaces intead of
reflection-based dispatch in order to improve performance overall. This
includes a custom wire protocol to significantly reduce the number of
allocations and take advantage of structure packing.
As part of these changes, there are a small number of minor changes in other
places of the code base:
* The lists used during encoding are changed to use intrusive lists with the
objectEncodeState directly, which required that the ilist Len() method is
updated to work properly with the ElementMapper mechanism.
* A bug is fixed in the list code wherein Remove() called on an element that is
already removed can corrupt the list (removing the element if there's only a
single element). Now the behavior is correct.
* Standard error wrapping is introduced.
* Compressio was updated to implement the new wire.Reader and wire.Writer
inteface methods directly. The lack of a ReadByte and WriteByte caused issues
not due to interface dispatch, but because underlying slices for a Read or
Write call through an interface would always escape to the heap!
* Statify has been updated to support the new APIs.
See README.md for a description of how the new mechanism works.
PiperOrigin-RevId: 318010298
* Rename syncutil to sync.
* Add aliases to sync types.
* Replace existing usage of standard library sync package.
This will make it easier to swap out synchronization primitives. For example,
this will allow us to use primitives from github.com/sasha-s/go-deadlock to
check for lock ordering violations.
Updates #1472
PiperOrigin-RevId: 289033387
Based on the guidelines at
https://opensource.google.com/docs/releasing/authors/.
1. $ rg -l "Google LLC" | xargs sed -i 's/Google LLC.*/The gVisor Authors./'
2. Manual fixup of "Google Inc" references.
3. Add AUTHORS file. Authors may request to be added to this file.
4. Point netstack AUTHORS to gVisor AUTHORS. Drop CONTRIBUTORS.
Fixes#209
PiperOrigin-RevId: 245823212
Change-Id: I64530b24ad021a7d683137459cafc510f5ee1de9
Nothing reads them and they can simply get stale.
Generated with:
$ sed -i "s/licenses(\(.*\)).*/licenses(\1)/" **/BUILD
PiperOrigin-RevId: 231818945
Change-Id: Ibc3f9838546b7e94f13f217060d31f4ada9d4bf0
This change also adds extensive testing to the p9 package via mocks. The sanity
checks and type checks are moved from the gofer into the core package, where
they can be more easily validated.
PiperOrigin-RevId: 218296768
Change-Id: I4fc3c326e7bf1e0e140a454cbacbcc6fd617ab55
Compared to previous compressio / hashio nesting, there is up to 100% speedup.
PiperOrigin-RevId: 210161269
Change-Id: I481aa9fe980bb817fe465fe34d32ea33fc8abf1c
We have been unnecessarily creating too many savable types implicitly.
PiperOrigin-RevId: 206334201
Change-Id: Idc5a3a14bfb7ee125c4f2bb2b1c53164e46f29a8
Ivan Prisyazhnyy