[PATCH 1/2] qemu: retain default trace backend if 'ust' is not enabled

[PATCH 1/2] qemu: retain default trace backend if 'ust' is not enabled

[Thomas De Schampheleire]

The qemu build system enables the 'log' trace backend by default, if no
explicit choice was made with '--enable-trace-backend=CHOICE'.

However, the qemu recipe uses the following PACKAGECONFIG line:
    PACKAGECONFIG[ust] = "--enable-trace-backend=ust,--enable-trace-backend=nop,lttng-ust,"

which means that the 'nop' trace backend will be explicitly selected if the
'ust' feature is not enabled. The 'nop' backend removes almost all trace
points at compile time, and thus basically means 'disable tracing'.

To retain the default trace backend if 'ust' is not enabled, the above
PACKAGECONFIG line should either explicitly fall back to the 'log' backend,
or not provide any value for the 'disabled' case. This commit chooses the
latter to not make any assumption about the upstream default.

Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
---
 meta/recipes-devtools/qemu/qemu.inc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc
index b41055fe5d..ae99a9e87b 100644
--- a/meta/recipes-devtools/qemu/qemu.inc
+++ b/meta/recipes-devtools/qemu/qemu.inc
@@ -207,7 +207,7 @@ PACKAGECONFIG[libudev] = "--enable-libudev,--disable-libudev,eudev"
 PACKAGECONFIG[attr] = "--enable-attr,--disable-attr,attr,"
 PACKAGECONFIG[rbd] = "--enable-rbd,--disable-rbd,ceph,ceph"
 PACKAGECONFIG[vhost] = "--enable-vhost-net,--disable-vhost-net,,"
-PACKAGECONFIG[ust] = "--enable-trace-backend=ust,--enable-trace-backend=nop,lttng-ust,"
+PACKAGECONFIG[ust] = "--enable-trace-backend=ust,,lttng-ust,"
 PACKAGECONFIG[pie] = "--enable-pie,--disable-pie,,"
 PACKAGECONFIG[seccomp] = "--enable-seccomp,--disable-seccomp,libseccomp"
 # libnfs is currently provided by meta-kodi
-- 
2.39.2

[PATCH 2/2] qemu: rename deprecated --enable-trace-backend configure option

[Thomas De Schampheleire]

qemu 6.2 deprecated the configure option '--enable-trace-backend' in favor
of '--enable-trace-backends' [1]

Rename accordingly.

[1] https://wiki.qemu.org/ChangeLog/6.2#Build_Information

Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
---
 meta/recipes-devtools/qemu/qemu.inc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc
index ae99a9e87b..f4426fc1f2 100644
--- a/meta/recipes-devtools/qemu/qemu.inc
+++ b/meta/recipes-devtools/qemu/qemu.inc
@@ -207,7 +207,7 @@ PACKAGECONFIG[libudev] = "--enable-libudev,--disable-libudev,eudev"
 PACKAGECONFIG[attr] = "--enable-attr,--disable-attr,attr,"
 PACKAGECONFIG[rbd] = "--enable-rbd,--disable-rbd,ceph,ceph"
 PACKAGECONFIG[vhost] = "--enable-vhost-net,--disable-vhost-net,,"
-PACKAGECONFIG[ust] = "--enable-trace-backend=ust,,lttng-ust,"
+PACKAGECONFIG[ust] = "--enable-trace-backends=ust,,lttng-ust,"
 PACKAGECONFIG[pie] = "--enable-pie,--disable-pie,,"
 PACKAGECONFIG[seccomp] = "--enable-seccomp,--disable-seccomp,libseccomp"
 # libnfs is currently provided by meta-kodi
-- 
2.39.2

Re: [OE-core] [PATCH 1/2] qemu: retain default trace backend if 'ust' is not enabled

[Richard Purdie]

On Mon, 2023-04-03 at 16:37 +0200, Thomas De Schampheleire wrote:
> The qemu build system enables the 'log' trace backend by default, if no
> explicit choice was made with '--enable-trace-backend=CHOICE'.
> 
> However, the qemu recipe uses the following PACKAGECONFIG line:
>     PACKAGECONFIG[ust] = "--enable-trace-backend=ust,--enable-trace-backend=nop,lttng-ust,"
> 
> which means that the 'nop' trace backend will be explicitly selected if the
> 'ust' feature is not enabled. The 'nop' backend removes almost all trace
> points at compile time, and thus basically means 'disable tracing'.
> 
> To retain the default trace backend if 'ust' is not enabled, the above
> PACKAGECONFIG line should either explicitly fall back to the 'log' backend,
> or not provide any value for the 'disabled' case. This commit chooses the
> latter to not make any assumption about the upstream default.
> 
> Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
> ---
>  meta/recipes-devtools/qemu/qemu.inc | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc
> index b41055fe5d..ae99a9e87b 100644
> --- a/meta/recipes-devtools/qemu/qemu.inc
> +++ b/meta/recipes-devtools/qemu/qemu.inc
> @@ -207,7 +207,7 @@ PACKAGECONFIG[libudev] = "--enable-libudev,--disable-libudev,eudev"
>  PACKAGECONFIG[attr] = "--enable-attr,--disable-attr,attr,"
>  PACKAGECONFIG[rbd] = "--enable-rbd,--disable-rbd,ceph,ceph"
>  PACKAGECONFIG[vhost] = "--enable-vhost-net,--disable-vhost-net,,"
> -PACKAGECONFIG[ust] = "--enable-trace-backend=ust,--enable-trace-backend=nop,lttng-ust,"
> +PACKAGECONFIG[ust] = "--enable-trace-backend=ust,,lttng-ust,"
>  PACKAGECONFIG[pie] = "--enable-pie,--disable-pie,,"
>  PACKAGECONFIG[seccomp] = "--enable-seccomp,--disable-seccomp,libseccomp"
>  # libnfs is currently provided by meta-kodi

This triggered reproducible build test failures:

https://autobuilder.yoctoproject.org/typhoon/#/builders/117/builds/2659/steps/12/logs/stdio

which leads to:

http://autobuilder.yocto.io/pub/repro-fail/oe-reproducible-20230403-itxd_s50/packages/diff-html/

i.e. the paths to files is being encoded the target source package
files.

We'll need to resolve that issue before we can turn the default tracing
on.

Cheers,

Richard

Re: [OE-core] [PATCH 1/2] qemu: retain default trace backend if 'ust' is not enabled

[Thomas De Schampheleire]

On Tue, Apr 04, 2023 at 11:05:05AM +0100, Richard Purdie wrote:
> This triggered reproducible build test failures:
> 
> https://autobuilder.yoctoproject.org/typhoon/#/builders/117/builds/2659/steps/12/logs/stdio
> 
> which leads to:
> 
> http://autobuilder.yocto.io/pub/repro-fail/oe-reproducible-20230403-itxd_s50/packages/diff-html/
> 
> i.e. the paths to files is being encoded the target source package
> files.
> 
> We'll need to resolve that issue before we can turn the default tracing
> on.

Thanks for reviewing/testing, v2 coming up where that should be fixed.

/Thomas