Do not hold bare pointers to scripts during sampling heap tree construction,
as string conversions may lead to an allocation that in turn could cause GC
which renders all pointers invalid.
Review-Url: https://codereview.chromium.org/1929813002
Cr-Commit-Position: refs/heads/master@{#35883}
Implements poisson unsampling. A poisson process is used to determine
which samples to collect based on a sample rate. Unsampling will
approximate the true number of allocations at each site taking into
account that smaller allocations are less likley to be sampled.
This work was originally being done in the agent that
consumes profiles but it is more efficient to do it here
and individual consumers of the API should not have to
worry about the mathematical details of the sampling
process.
R=ofrobots@google.com
BUG=
Review URL: https://codereview.chromium.org/1706343002
Cr-Commit-Position: refs/heads/master@{#34234}
Reason for revert:
Failure keeps lurking around after the revert. I'll reland, sorry for the inconvenience!
Original issue's description:
> Revert of Sampling heap profiler data structure changes (patchset #10 id:180001 of https://codereview.chromium.org/1697903002/ )
>
> Reason for revert:
> [Sheriff] Speculative revert for cpu profiler crashes on chromebooks:
> https://build.chromium.org/p/client.v8/builders/V8%20Arm%20-%20debug/builds/549
> https://build.chromium.org/p/client.v8/builders/V8%20Arm%20-%20debug/builds/550
>
> Original issue's description:
> > Sampling heap profiler data structure changes
> >
> > Previously, the sampling heap profiler stored a list of samples and then
> > built a tree representation when the profile was queried by calling
> > GetAllocationProfile. This change reduces duplication by removing stacks
> > from all samples. Also, less information is stored in the tree
> > maintained by the profiler and remaining information (script name, line
> > no, etc) is resolved when a profile is requested.
> >
> > BUG=
> >
> > Committed: https://crrev.com/cdd55e2a3717723492d76f66810bf56b8de7f198
> > Cr-Commit-Position: refs/heads/master@{#34119}
>
> TBR=ofrobots@google.com,ulan@chromium.org,hpayer@chromium.org,mattloring@google.com
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=
>
> Committed: https://crrev.com/4578e52aefb8c4727742ce2e254613e482fdad1f
> Cr-Commit-Position: refs/heads/master@{#34128}
TBR=ofrobots@google.com,ulan@chromium.org,hpayer@chromium.org,mattloring@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
Review URL: https://codereview.chromium.org/1714493003
Cr-Commit-Position: refs/heads/master@{#34140}
Reason for revert:
[Sheriff] Speculative revert for cpu profiler crashes on chromebooks:
https://build.chromium.org/p/client.v8/builders/V8%20Arm%20-%20debug/builds/549https://build.chromium.org/p/client.v8/builders/V8%20Arm%20-%20debug/builds/550
Original issue's description:
> Sampling heap profiler data structure changes
>
> Previously, the sampling heap profiler stored a list of samples and then
> built a tree representation when the profile was queried by calling
> GetAllocationProfile. This change reduces duplication by removing stacks
> from all samples. Also, less information is stored in the tree
> maintained by the profiler and remaining information (script name, line
> no, etc) is resolved when a profile is requested.
>
> BUG=
>
> Committed: https://crrev.com/cdd55e2a3717723492d76f66810bf56b8de7f198
> Cr-Commit-Position: refs/heads/master@{#34119}
TBR=ofrobots@google.com,ulan@chromium.org,hpayer@chromium.org,mattloring@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=
Review URL: https://codereview.chromium.org/1708363002
Cr-Commit-Position: refs/heads/master@{#34128}
Previously, the sampling heap profiler stored a list of samples and then
built a tree representation when the profile was queried by calling
GetAllocationProfile. This change reduces duplication by removing stacks
from all samples. Also, less information is stored in the tree
maintained by the profiler and remaining information (script name, line
no, etc) is resolved when a profile is requested.
BUG=
Review URL: https://codereview.chromium.org/1697903002
Cr-Commit-Position: refs/heads/master@{#34119}
This change expands allocation sampling to include old, map, code, and large object spaces. This involved refactoring much of the observation logic out of NewSpace into Space and overriding as needed in sub-classes.
Additionally, the sampling heap profiler now maintains a pair of heap observers. One observer is used for observing new space and resetting the inline allocation limit to be periodically notified of allocations. The other observes allocation across the other spaces where there is no additional work required to observe allocations.
Tests have been updated to ensure that allocations are observed correctly for Paged and LargeObject spaces.
R=ofrobots@google.com, hpayer@chromium.org, ulan@chromium.org
BUG=
Review URL: https://codereview.chromium.org/1625753002
Cr-Commit-Position: refs/heads/master@{#33959}
Reason for revert:
The random nature of the tests caused the following buildbot to fail: https://build.chromium.org/p/client.v8/builders/V8%20Linux%20gcc%204.8/builds/4724/steps/Check/logs/stdio
Original issue's description:
> [profiler] Implement POC Sampling Heap Profiler
>
> This implements a proof-of-concept sampling based heap profiler inspired by
> tcmalloc's heap profiler [1] and Go's mprof/memprofile [2].
>
> The basic idea is the sample allocations using a randomized Poisson process. At
> any point in time we can cheaply request the set of live sample objects that
> should be a representative sample of heap. Samples include stack-traces from the
> allocation sites, making this an effective tool for memory leak debugging.
>
> Unlike AllocationTracking, this is intended to be cheap and usable online in
> production.
>
> The proof-of-concept is only sampling new-space allocations at this point.
> Support for sampling paged space and native allocations is anticipated in the
> future.
>
> [1] http://goog-perftools.sourceforge.net/doc/heap_profiler.html
> [2] http://blog.golang.org/profiling-go-programs
>
> Committed: https://crrev.com/e5a9947811db9c9e23557dbad27f8b8a349b3262
> Cr-Commit-Position: refs/heads/master@{#33448}
TBR=jochen@chromium.org,alph@chromium.org,hpayer@chromium.org,yangguo@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
Review URL: https://codereview.chromium.org/1615173002
Cr-Commit-Position: refs/heads/master@{#33449}
This implements a proof-of-concept sampling based heap profiler inspired by
tcmalloc's heap profiler [1] and Go's mprof/memprofile [2].
The basic idea is the sample allocations using a randomized Poisson process. At
any point in time we can cheaply request the set of live sample objects that
should be a representative sample of heap. Samples include stack-traces from the
allocation sites, making this an effective tool for memory leak debugging.
Unlike AllocationTracking, this is intended to be cheap and usable online in
production.
The proof-of-concept is only sampling new-space allocations at this point.
Support for sampling paged space and native allocations is anticipated in the
future.
[1] http://goog-perftools.sourceforge.net/doc/heap_profiler.html
[2] http://blog.golang.org/profiling-go-programs
Review URL: https://codereview.chromium.org/1555553002
Cr-Commit-Position: refs/heads/master@{#33448}
