linux-toradex.git/arch/powerpc/include/asm/vdso.h, branch v3.2.71 Linux kernel for Apalis and Colibri modules powerpc: Move 64bit VDSO to improve context switch performance 2009-08-20T00:12:24+00:00 Anton Blanchard anton@samba.org 2009-07-13T20:53:51+00:00 30d0b3682887a81f0335b42f20116fd40d743371 On 64bit applications the VDSO is the only thing in segment 0. Since the VDSO is position independent we can remove the hint and let get_unmapped_area pick an area. This will mean the vdso will be near other mmaps and will share an SLB entry: 10000000-10001000 r-xp 00000000 08:06 5778459 /root/context_switch_64 10010000-10011000 r--p 00000000 08:06 5778459 /root/context_switch_64 10011000-10012000 rw-p 00001000 08:06 5778459 /root/context_switch_64 fffa92ae000-fffa92b0000 rw-p 00000000 00:00 0 fffa92b0000-fffa9453000 r-xp 00000000 08:06 4334051 /lib64/power6/libc-2.9.so fffa9453000-fffa9462000 ---p 001a3000 08:06 4334051 /lib64/power6/libc-2.9.so fffa9462000-fffa9466000 r--p 001a2000 08:06 4334051 /lib64/power6/libc-2.9.so fffa9466000-fffa947c000 rw-p 001a6000 08:06 4334051 /lib64/power6/libc-2.9.so fffa947c000-fffa9480000 rw-p 00000000 00:00 0 fffa9480000-fffa94a8000 r-xp 00000000 08:06 4333852 /lib64/ld-2.9.so fffa94b3000-fffa94b4000 rw-p 00000000 00:00 0 fffa94b4000-fffa94b7000 r-xp 00000000 00:00 0 [vdso] <----- here I am fffa94b7000-fffa94b8000 r--p 00027000 08:06 4333852 /lib64/ld-2.9.so fffa94b8000-fffa94bb000 rw-p 00028000 08:06 4333852 /lib64/ld-2.9.so fffa94bb000-fffa94bc000 rw-p 00000000 00:00 0 fffe4c10000-fffe4c25000 rw-p 00000000 00:00 0 [stack] On a microbenchmark that bounces a token between two 64bit processes over pipes and calls gettimeofday each iteration (to access the VDSO), our context switch rate goes from 268k to 277k ctx switches/sec (tested on a 4GHz POWER6). Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> 
On 64bit applications the VDSO is the only thing in segment 0. Since the VDSO
is position independent we can remove the hint and let get_unmapped_area pick
an area. This will mean the vdso will be near other mmaps and will share
an SLB entry:

10000000-10001000 r-xp 00000000 08:06 5778459        /root/context_switch_64
10010000-10011000 r--p 00000000 08:06 5778459        /root/context_switch_64
10011000-10012000 rw-p 00001000 08:06 5778459        /root/context_switch_64
fffa92ae000-fffa92b0000 rw-p 00000000 00:00 0
fffa92b0000-fffa9453000 r-xp 00000000 08:06 4334051  /lib64/power6/libc-2.9.so
fffa9453000-fffa9462000 ---p 001a3000 08:06 4334051  /lib64/power6/libc-2.9.so
fffa9462000-fffa9466000 r--p 001a2000 08:06 4334051  /lib64/power6/libc-2.9.so
fffa9466000-fffa947c000 rw-p 001a6000 08:06 4334051  /lib64/power6/libc-2.9.so
fffa947c000-fffa9480000 rw-p 00000000 00:00 0
fffa9480000-fffa94a8000 r-xp 00000000 08:06 4333852  /lib64/ld-2.9.so
fffa94b3000-fffa94b4000 rw-p 00000000 00:00 0

fffa94b4000-fffa94b7000 r-xp 00000000 00:00 0        [vdso] <----- here I am

fffa94b7000-fffa94b8000 r--p 00027000 08:06 4333852  /lib64/ld-2.9.so
fffa94b8000-fffa94bb000 rw-p 00028000 08:06 4333852  /lib64/ld-2.9.so
fffa94bb000-fffa94bc000 rw-p 00000000 00:00 0
fffe4c10000-fffe4c25000 rw-p 00000000 00:00 0        [stack]

On a microbenchmark that bounces a token between two 64bit processes over pipes
and calls gettimeofday each iteration (to access the VDSO), our context switch
rate goes from 268k to 277k ctx switches/sec (tested on a 4GHz POWER6).

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
powerpc: Move include files to arch/powerpc/include/asm 2008-08-04T02:02:00+00:00 Stephen Rothwell sfr@canb.auug.org.au 2008-08-01T05:20:30+00:00 b8b572e1015f81b4e748417be2629dfe51ab99f9 from include/asm-powerpc. This is the result of a mkdir arch/powerpc/include/asm git mv include/asm-powerpc/* arch/powerpc/include/asm Followed by a few documentation/comment fixups and a couple of places where <asm-powepc/...> was being used explicitly. Of the latter only one was outside the arch code and it is a driver only built for powerpc. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paul Mackerras <paulus@samba.org> 
from include/asm-powerpc.  This is the result of a

mkdir arch/powerpc/include/asm
git mv include/asm-powerpc/* arch/powerpc/include/asm

Followed by a few documentation/comment fixups and a couple of places
where <asm-powepc/...> was being used explicitly.  Of the latter only
one was outside the arch code and it is a driver only built for powerpc.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>