Hello,
On Mon, Feb 09, 2026 at 06:07:59PM +0100, Jens Remus wrote:
On 2/5/2026 7:54 PM, Steven Rostedt wrote:
quoted
On Thu, 5 Feb 2026 10:26:10 -0800
Namhyung Kim [off-list ref] wrote:
quoted
quoted
Namhyung Kim's related perf tools deferred callchain support can be used
for testing ("perf record --call-graph fp,defer" and "perf report/script").
Is it possible for users to choose the unwinder - frame pointer or
SFrame at runtime? I feel like the option should be
"--call-graph sframe,defer" or just "--call-graph sframe" if it always
uses deferred unwinding.
Currently no, and I'm not sure we want that do we? The idea is to use the
best option that is available. Why use frame pointers if sframe is
available and it's being called with defer?
If there's no defer, then sframes are not available, so it defaults to the
best option available (which will likely be frame pointers).
Users (me, at least) may want to compare stacktraces from FP and SFrame?
Maybe it would make sense not to "overload" the perf record option
"--call-graph fp,defer" and use it for all deferred unwinding methods.
What about "--call-graph defer", "--call-graph any,defer", or
"--call-graph *,defer"?
Sounds better. But I think it cannot enforce "--call-graph fp,defer" to
use frame pointers when SFrame is available.. Hmm.
Thanks,
Namhyung