Re: [PATCH v2 08/18] perf test cs-etm: Replace memcpy test with raw dump stress test

[Leo Yan <leo.yan@arm.com>]

On Wed, Jun 03, 2026 at 05:11:30PM +0100, James Clark wrote:

[...]

> > I am not sure how we can map 2MiB trace data to 50MiB+ raw dump.  This
> 
> Why not? Decoding it is roughly equal to decompressing it, and with that
> amount of trace the small differences in compressibility average out and you
> do get the same amount every time. I think if we got less than half the
> amount expected then it would be worth investigating.

TBH, I don't know how to calculate decompressing size. Seems to me this
is a heuristics value.

Maybe Mike could help to confirm if this works or not.

[...]

> That would work, but that wouldn't be as thorough. The first thing it prints
> is " CoreSight .* Trace data: size .* bytes". If it stops working half way
> through or prints nothing then the test will still pass.
> 
> The reason I wanted to add a stress test is because all of the other tests
> have been reduced to just a few kb of trace so we have nothing that opens a
> file with a more reasonable amount of data.
> 
> I suppose with your suggestion we'd still check the exit code, but that's
> about it.

Is it possible to locate the end of raw dump with a specific parttern? like:

  Idx:36061; ID:1a;       I_IGNORE : Ignore.
  Idx:36062; ID:1a;       I_IGNORE : Ignore.
  Idx:36063; ID:1a;       I_IGNORE : Ignore.
  Idx:36064; ID:1a;       I_IGNORE : Ignore.
  Idx:36065; ID:1a;       I_IGNORE : Ignore.
  Idx:36066; ID:1a;       I_IGNORE : Ignore.
  Idx:36067; ID:1a;       I_IGNORE : Ignore.
  Idx:36068; ID:1a;       I_IGNORE : Ignore.
  Idx:36069; ID:1a;       I_IGNORE : Ignore.
  Idx:36070; ID:1a;       I_IGNORE : Ignore.
  Idx:36071; ID:1a;       I_IGNORE : Ignore.
  Idx:36072; ID:1a;       I_IGNORE : Ignore.
  Idx:36073; ID:1a;       I_IGNORE : Ignore.
  Idx:36074; ID:1a;       I_IGNORE : Ignore.
  Idx:36075; ID:1a;       I_IGNORE : Ignore.
  Idx:36076; ID:1a;       I_IGNORE : Ignore.
  Idx:36077; ID:1a;       I_IGNORE : Ignore.
  Idx:36078; ID:1a;       I_IGNORE : Ignore.
  Idx:36079; ID:1a;       I_IGNORE : Ignore.
  Idx:36080; ID:1a;       I_IGNORE : Ignore.
  Idx:36081; ID:1a;       I_IGNORE : Ignore.
  Idx:36082; ID:1a;       I_IGNORE : Ignore.
  Idx:36083; ID:1a;       I_IGNORE : Ignore.
  Idx:36084; ID:1a;       I_IGNORE : Ignore.
  Idx:36085; ID:1a;       I_IGNORE : Ignore.
  Idx:36086; ID:1a;       I_IGNORE : Ignore.
  Idx:36087; ID:1a;       I_IGNORE : Ignore.
  Idx:36088; ID:1a;       I_IGNORE : Ignore.
  Idx:36089; ID:1a;       I_IGNORE : Ignore.
  Idx:36090; ID:1a;       I_IGNORE : Ignore.
  Idx:36091; ID:1a;       I_IGNORE : Ignore.
  Idx:36092; ID:1a;       I_IGNORE : Ignore.
  Idx:36093; ID:1a;       I_IGNORE : Ignore.
  Idx:36094; ID:1a;       I_IGNORE : Ignore.
  Idx:36095; ID:1a;       I_IGNORE : Ignore.

Thanks,
Leo