[oe] [oe-commits] Pratheesh Gangadhar : glib-2.0 2.21.4: add armv6 atomic ops, this fixes 100% utilization hangs when doing DSP based GStreamer playback

[Koen Kooi]

On 28-08-09 14:50, Marcin Juszkiewicz wrote:
> Dnia czwartek, 27 sierpnia 2009 o 16:05:21 git version control napisał(a):
>> Module: openembedded.git
>> Branch: org.openembedded.dev
>> Commit: 1eb89aacbc6830fe242eac36ba8bcb61d98807f5
>> URL:
>>   http://gitweb.openembedded.net/?p=openembedded.git&a=commit;h=1eb89aacbc68
>> 30fe242eac36ba8bcb61d98807f5
>>
>> Author: Pratheesh Gangadhar<pratheesh.gangadhar at gmail.com>
>> Date:   Thu Aug 27 02:51:00 2009 +0530
>>
>> glib-2.0 2.21.4: add armv6 atomic ops, this fixes 100% utilization hangs
>> when doing DSP based GStreamer playback
>>
>> GLIB by default uses ARMV5 instructions for emulating atomic operations and
>> this patch (derived from
>> https://stage.maemo.org/svn/maemo/projects/haf/trunk/glib/debian/patches/25
>> -gatomic.patch) make use ARMV6 atomic instructions instead. CPU goes into
>> "sched_yield" while loop during hang - due to a race condition triggered by
>>   high rate context switching while running DSP plugins.
>
> 1. Your change reverted PR from r4 (set in glib.inc) to r1

I overlooked that when reviewing, sorry

> 2. This is not buildable for arm<6:
>
> | arm-angstrom-linux-gnueabi-libtool: compile:  ccache arm-angstrom-linux-gnueabi-gcc -march=armv5te -mtune=arm926ej-s -mthumb-interwork -mno-thumb -D
> HAVE_CONFIG_H -I. -I.. -I.. -DG_LOG_DOMAIN=\"GLib\" -DG_DISABLE_CAST_CHECKS -DG_DISABLE_ASSERT -DG_DISABLE_CHECKS -DG_DISABLE_DEPRECATED -DGLIB_COMPIL
> ATION -DPCRE_STATIC -isystem/home/hrw/devel/build/angstrom/tmp/staging/armv5te-angstrom-linux-gnueabi/usr/include -DG_DISABLE_SINGLE_INCLUDES -pthread
>   -isystem/home/hrw/devel/build/angstrom/tmp/staging/armv5te-angstrom-linux-gnueabi/usr/include -fexpensive-optimizations -frename-registers -fomit-frame-
> pointer -O2 -ggdb3 -Wall -mno-thumb -isystem/home/hrw/devel/build/angstrom/tmp/staging/armv5te-angstrom-linux-gnueabi/usr/include -fexpensive-optimizations -
> frename-registers -fomit-frame-pointer -O2 -ggdb3 -Wall -MT libgatomic_la-gatomic.lo -MD -MP -MF .deps/libgatomic_la-gatomic.Tpo -c gatomic.c  -fPIC -DPIC -o
> .libs/libgatomic_la-gatomic.o
> | /tmp/ccEqvIUs.s: Assembler messages:
> | /tmp/ccEqvIUs.s:9449: Error: selected processor does not support `ldrex r0,[r2]'
> | /tmp/ccEqvIUs.s:9451: Error: selected processor does not support `strex r3,ip,[r2]'
> | /tmp/ccEqvIUs.s:9477: Error: selected processor does not support `ldrex r2,[r0]'
> | /tmp/ccEqvIUs.s:9479: Error: selected processor does not support `strex r3,r2,[r0]'
> | /tmp/ccEqvIUs.s:9504: Error: selected processor does not support `ldrex r3,[r0]'
> | /tmp/ccEqvIUs.s:9507: Error: selected processor does not support `strexeq ip,r2,[r0]'
> | /tmp/ccEqvIUs.s:9532: Error: selected processor does not support `ldrex r3,[r0]'
> | /tmp/ccEqvIUs.s:9535: Error: selected processor does not support `strexeq ip,r2,[r0]'
> | /tmp/ccEqvIUs.s:9577: Error: selected processor does not support `ldrex r3,[r0]'
> | /tmp/ccEqvIUs.s:9578: Error: selected processor does not support `strex r3,r1,[r0]'
> | /tmp/ccEqvIUs.s:9620: Error: selected processor does not support `ldrex r3,[r0]'
> | /tmp/ccEqvIUs.s:9621: Error: selected processor does not support `strex r3,r1,[r0]'
> | make[4]: *** [libgatomic_la-gatomic.lo] Error 1
> | make[4]: *** Waiting for unfinished jobs....

That's weird, since that's all wrapped in 'if G_ATOMIC_ARM > 6', but I 
made the patch armv6 and armv7 only to be really sure. Thanks for 
finding this issue.

regards,

Koen