Re: [PATCH v5 0/7] perf libunwind multiple remote support

From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Ian Rogers <irogers@google.com>
Cc: adrian.hunter@intel.com, dapeng1.mi@linux.intel.com,
	james.clark@linaro.org, namhyung@kernel.org,
	Florian Fainelli <florian.fainelli@broadcom.com>,
	Li Guan <guanli.oerv@isrc.iscas.ac.cn>,
	9erthalion6@gmail.com, alex@ghiti.fr,
	alexander.shishkin@linux.intel.com,
	andrew.jones@oss.qualcomm.com, aou@eecs.berkeley.edu,
	atrajeev@linux.ibm.com, howardchu95@gmail.com,
	john.g.garry@oracle.com, jolsa@kernel.org, leo.yan@linux.dev,
	libunwind-devel@nongnu.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
	linux-riscv@lists.infradead.org, mingo@redhat.com,
	palmer@dabbelt.com, peterz@infradead.org, pjw@kernel.org,
	shimin.guo@skydio.com, tglozar@redhat.com, tmricht@linux.ibm.com,
	will@kernel.org
Subject: Re: [PATCH v5 0/7] perf libunwind multiple remote support
Date: Thu, 14 May 2026 21:01:15 -0300	[thread overview]
Message-ID: <agZiS2-fY49MjsY6@x1> (raw)
In-Reply-To: <CAP-5=fW6S1XzZvq=kWj6ma=O1UCDrVV3ZNbzK0fMS_ho6e1qVg@mail.gmail.com>

On Thu, May 14, 2026 at 09:51:09AM -0700, Ian Rogers wrote:
> On Wed, May 13, 2026 at 4:32 PM Ian Rogers <irogers@google.com> wrote:
> > Fix the libunwind build for when libdw and libunwind are feature
> > detected, currently failing with a duplicate symbol.
> >
> > Refactor the libunwind support so that whenever a remote target is
> > available, perf functions using the ELF machine can use that remote
> > target regardless of what the host/local machine is. Migrate existing
> > libunwind supported architectures like powerpc, arm64 and loongarch so
> > that they can work in a cross-architecture way. Add support for
> > RISC-V. Make the code more regular in function names, etc. and avoid
> > including a C-file. This increases the lines of code. It is similar in
> > style to the unwind-libdw implementation. It is hoped that the more
> > uniform nature of the code will help with refactoring the perf
> > registers for SIMD/APX support.
> >
> > Aside from local host testing these patches are under tested, in part
> > as I'm failing to see how to build libunwind with support for multiple
> > remote targets. Please could I get help in testing.
> 
> So the patches failed to apply in Sashiko:
> https://sashiko.dev/#/patchset/20260513233151.572332-1-irogers%40google.com
> The baseline logs show perf-tools-next was at commit 8c8f20936143
> ("perf build: Remove NO_GTK2 build test") which is 6 patches
> out-of-date compared to the current tip these patches are against. I
> ran Sashiko locally, so I don't expect a huge amount from the reviews.
> Currently Sashiko is catching up with a backlog because its tokens
> have a lower priority and there was high load earlier in the week.
> Anyway, I could repost the patches for Sashiko review but given the
> backlog I think that would just create noise at the moment. Hopefully
> I can get human review so we can move forward with merging these
> improvements.

Trying to apply it now, will also run sashiko locally.

- Arnaldo

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