Re: [RFC 6/6] perf build: Introduce FEATURES_DUMP make variable
From: Wangnan (F)
Date: Tue Jan 12 2016 - 04:29:29 EST
On 2016/1/11 18:54, Jiri Olsa wrote:
Introducing FEATURES_DUMP make variable to provide features
detection dump file and bypass the feature detection.
The intention is to use this during build tests to skip
repeated features detection, like:
Get feature dump static build into /tmp/fd file:
$ make feature-dump FEATURE_DUMP_COPY=/tmp/fd LDFLAGS=-static
BUILD: Doing 'make -j4' parallel build
Auto-detecting system features:
... dwarf: [ OFF ]
SNIP
FEATURE-DUMP file copied into /tmp/fd
Use /tmp/fd to build perf:
$ make FEATURES_DUMP=/tmp/fd LDFLAGS=-static
$ file perf
perf: ELF 64-bit LSB executable, x86-64, version 1 (GNU/Linux), statically linked, for ...
Suggested-by: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-fhb47m6t18txuwrzu33is2bo@xxxxxxxxxxxxxx
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
Thank you for these two patch. However I found a small limitation.
I must skip 'make clean' between two feature-dump, or the result is wrong.
For example:
$ make feature-dump LDFLAGS="-static"
BUILD: Doing 'make -j24' parallel build
Auto-detecting system features:
<SNIP>
... zlib: [ on ]
... lzma: [ OFF ] <--- looks good. I don't
have static lzma library
... get_cpuid: [ on ]
... bpf: [ on ]
$ make feature-dump
BUILD: Doing 'make -j24' parallel build
Auto-detecting system features:
<SNIP>
... zlib: [ on ]
... lzma: [ on ] <--- also good
... get_cpuid: [ on ]
... bpf: [ on ]
$ make feature-dump LDFLAGS="-static"
BUILD: Doing 'make -j24' parallel build
Auto-detecting system features:
<SNIP>
... zlib: [ on ]
... lzma: [ on ] <--- Bad...
... get_cpuid: [ on ]
... bpf: [ on ]
Thank you.