This is follow up to commit cb0c2bf5ed.
SampleBlockProcessor only enters isolate group and not a specific
isolate so the code must not rely on thread->isolate(). This fixes two
places where this was not the case:
* ProfileBuilder::IsPCInDartHeap
* UserTags::TagName
pkg/dds/test/get_cached_cpu_samples_test was supposed to cover this but
it has two problems:
First I observed that SampleBlockProcessor never gets a chance to
process a block if mutator thread always gets to it first (via a
scheduled interrupt), so this code is not well exercised. I started by
adding a variant of the test where interrupts are inhibited via a
vm:unsafe:no-interrupts pragma - which revealed the crashes in the
SampleBlockProcessor code.
This revealed the second problem: get_cached_cpu_samples_test does not
actually fail if testee crashes during the test, it just silently
completes with success. This seems to happen because disposal of
VmService connection is not forwarded into the future on which the test
is awaiting - and the whole process just exits once VmService connection
to the testee disappears (because all ports are closed, no pending
activity is possible after that one). I have fixed this by adding a
helper function which checks that connection to VmService only goes away
when we dispose it.
Note: there is another obvious issue here, which I am leaving unfixed
for now. SampleBlockProcessor calls UserTags::TagName in a way that can
race with isolate itself modifying the table. I think this race is
extremely unlikely but it can cause crashes on ARMs with its weak memory
model (e.g. we might end up reading garbage due to the reordering of
stores).
TEST=pkg/dds/test/get_cached_cpu_samples_test
Change-Id: Iee15ec2b019928b798c312e63edc76696abf5527
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/426300
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>
This reverts commit 1796160606.
Reason for revert: Still seeing failures.
Original change's description:
> Reland "[ package:dds ] Add support for caching CPU samples based on UserTag"
>
> This reverts commit 4160747ef6.
>
> It seems like 9397b8ff05 should have fixed the original failures we were seeing and the failing bots in question seem to be passing when running try jobs.
>
> TBR=asiva@ (discussed offline)
>
> TEST=Existing service tests + get_cached_cpu_samples_test
> Change-Id: I1c50c0e79375df819a0bd68e68ac28c3064874c8
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/208441
> Reviewed-by: Ben Konyi <bkonyi@google.com>
> Commit-Queue: Ben Konyi <bkonyi@google.com>
TBR=bkonyi@google.com,asiva@google.com
Change-Id: Ic522ab61b430673533c94ecd0c91bee569a0add6
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/208960
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Ben Konyi <bkonyi@google.com>
This reverts commit 4160747ef6.
It seems like 9397b8ff05 should have fixed the original failures we were seeing and the failing bots in question seem to be passing when running try jobs.
TBR=asiva@ (discussed offline)
TEST=Existing service tests + get_cached_cpu_samples_test
Change-Id: I1c50c0e79375df819a0bd68e68ac28c3064874c8
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/208441
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Ben Konyi <bkonyi@google.com>
DDS can be configured to listen for CPU sample events and cache samples
that were collected while certain UserTags are active. These cached
samples are stored in a ring buffer and are stored until the isolate
shuts down.
TEST=pkg/dds/test/get_cached_cpu_samples_test.dart
Change-Id: Ib20770f59f1672c703413486f87795b3bb23f676
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/207206
Commit-Queue: Ben Konyi <bkonyi@google.com>
Reviewed-by: Kenzie Schmoll <kenzieschmoll@google.com>
Derek Xu