From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH] powerpc: force inlining of csum_partial() to avoid multiple csum_partial() with GCC10
Date: Thu, 15 Oct 2020 10:52:20 +0000 (UTC) [thread overview]
Message-ID: <a1d31f84ddb0926813b17fcd5cc7f3fa7b4deac2.1602759123.git.christophe.leroy@csgroup.eu> (raw)
ppc-linux-objdump -d vmlinux | grep -e "<csum_partial>" -e "<__csum_partial>"
With gcc9 I get:
c0017ef8 <__csum_partial>:
c00182fc: 4b ff fb fd bl c0017ef8 <__csum_partial>
c0018478: 4b ff fa 80 b c0017ef8 <__csum_partial>
c03e8458: 4b c2 fa a0 b c0017ef8 <__csum_partial>
c03e8518: 4b c2 f9 e1 bl c0017ef8 <__csum_partial>
c03ef410: 4b c2 8a e9 bl c0017ef8 <__csum_partial>
c03f0b24: 4b c2 73 d5 bl c0017ef8 <__csum_partial>
c04279a4: 4b bf 05 55 bl c0017ef8 <__csum_partial>
c0429820: 4b be e6 d9 bl c0017ef8 <__csum_partial>
c0429944: 4b be e5 b5 bl c0017ef8 <__csum_partial>
c042b478: 4b be ca 81 bl c0017ef8 <__csum_partial>
c042b554: 4b be c9 a5 bl c0017ef8 <__csum_partial>
c045f15c: 4b bb 8d 9d bl c0017ef8 <__csum_partial>
c0492190: 4b b8 5d 69 bl c0017ef8 <__csum_partial>
c0492310: 4b b8 5b e9 bl c0017ef8 <__csum_partial>
c0495594: 4b b8 29 65 bl c0017ef8 <__csum_partial>
c049c420: 4b b7 ba d9 bl c0017ef8 <__csum_partial>
c049c870: 4b b7 b6 89 bl c0017ef8 <__csum_partial>
c049c930: 4b b7 b5 c9 bl c0017ef8 <__csum_partial>
c04a9ca0: 4b b6 e2 59 bl c0017ef8 <__csum_partial>
c04bdde4: 4b b5 a1 15 bl c0017ef8 <__csum_partial>
c04be480: 4b b5 9a 79 bl c0017ef8 <__csum_partial>
c04be710: 4b b5 97 e9 bl c0017ef8 <__csum_partial>
c04c969c: 4b b4 e8 5d bl c0017ef8 <__csum_partial>
c04ca2fc: 4b b4 db fd bl c0017ef8 <__csum_partial>
c04cf5bc: 4b b4 89 3d bl c0017ef8 <__csum_partial>
c04d0440: 4b b4 7a b9 bl c0017ef8 <__csum_partial>
With gcc10 I get:
c0018d08 <__csum_partial>:
c0019020 <csum_partial>:
c0019020: 4b ff fc e8 b c0018d08 <__csum_partial>
c001914c: 4b ff fe d4 b c0019020 <csum_partial>
c0019250: 4b ff fd d1 bl c0019020 <csum_partial>
c03e404c <csum_partial>:
c03e404c: 4b c3 4c bc b c0018d08 <__csum_partial>
c03e4050: 4b ff ff fc b c03e404c <csum_partial>
c03e40fc: 4b ff ff 51 bl c03e404c <csum_partial>
c03e6680: 4b ff d9 cd bl c03e404c <csum_partial>
c03e68c4: 4b ff d7 89 bl c03e404c <csum_partial>
c03e7934: 4b ff c7 19 bl c03e404c <csum_partial>
c03e7bf8: 4b ff c4 55 bl c03e404c <csum_partial>
c03eb148: 4b ff 8f 05 bl c03e404c <csum_partial>
c03ecf68: 4b c2 bd a1 bl c0018d08 <__csum_partial>
c04275b8 <csum_partial>:
c04275b8: 4b bf 17 50 b c0018d08 <__csum_partial>
c0427884: 4b ff fd 35 bl c04275b8 <csum_partial>
c0427b18: 4b ff fa a1 bl c04275b8 <csum_partial>
c0427bd8: 4b ff f9 e1 bl c04275b8 <csum_partial>
c0427cd4: 4b ff f8 e5 bl c04275b8 <csum_partial>
c0427e34: 4b ff f7 85 bl c04275b8 <csum_partial>
c045a1c0: 4b bb eb 49 bl c0018d08 <__csum_partial>
c0489464 <csum_partial>:
c0489464: 4b b8 f8 a4 b c0018d08 <__csum_partial>
c04896b0: 4b ff fd b5 bl c0489464 <csum_partial>
c048982c: 4b ff fc 39 bl c0489464 <csum_partial>
c0490158: 4b b8 8b b1 bl c0018d08 <__csum_partial>
c0492f0c <csum_partial>:
c0492f0c: 4b b8 5d fc b c0018d08 <__csum_partial>
c049326c: 4b ff fc a1 bl c0492f0c <csum_partial>
c049333c: 4b ff fb d1 bl c0492f0c <csum_partial>
c0493b18: 4b ff f3 f5 bl c0492f0c <csum_partial>
c0493f50: 4b ff ef bd bl c0492f0c <csum_partial>
c0493ffc: 4b ff ef 11 bl c0492f0c <csum_partial>
c04a0f78: 4b b7 7d 91 bl c0018d08 <__csum_partial>
c04b3e3c: 4b b6 4e cd bl c0018d08 <__csum_partial>
c04b40d0 <csum_partial>:
c04b40d0: 4b b6 4c 38 b c0018d08 <__csum_partial>
c04b4448: 4b ff fc 89 bl c04b40d0 <csum_partial>
c04b46f4: 4b ff f9 dd bl c04b40d0 <csum_partial>
c04bf448: 4b b5 98 c0 b c0018d08 <__csum_partial>
c04c5264: 4b b5 3a a5 bl c0018d08 <__csum_partial>
c04c61e4: 4b b5 2b 25 bl c0018d08 <__csum_partial>
gcc10 defines multiple versions of csum_partial() which are just
an unconditionnal branch to __csum_partial().
To enforce inlining of that branch to __csum_partial(),
mark csum_partial() as __always_inline.
With this patch with gcc10:
c0018d08 <__csum_partial>:
c0019148: 4b ff fb c0 b c0018d08 <__csum_partial>
c001924c: 4b ff fa bd bl c0018d08 <__csum_partial>
c03e40ec: 4b c3 4c 1d bl c0018d08 <__csum_partial>
c03e4120: 4b c3 4b e8 b c0018d08 <__csum_partial>
c03eb004: 4b c2 dd 05 bl c0018d08 <__csum_partial>
c03ecef4: 4b c2 be 15 bl c0018d08 <__csum_partial>
c0427558: 4b bf 17 b1 bl c0018d08 <__csum_partial>
c04286e4: 4b bf 06 25 bl c0018d08 <__csum_partial>
c0428cd8: 4b bf 00 31 bl c0018d08 <__csum_partial>
c0428d84: 4b be ff 85 bl c0018d08 <__csum_partial>
c045a17c: 4b bb eb 8d bl c0018d08 <__csum_partial>
c0489450: 4b b8 f8 b9 bl c0018d08 <__csum_partial>
c0491860: 4b b8 74 a9 bl c0018d08 <__csum_partial>
c0492eec: 4b b8 5e 1d bl c0018d08 <__csum_partial>
c04a0eac: 4b b7 7e 5d bl c0018d08 <__csum_partial>
c04b3e34: 4b b6 4e d5 bl c0018d08 <__csum_partial>
c04b426c: 4b b6 4a 9d bl c0018d08 <__csum_partial>
c04b463c: 4b b6 46 cd bl c0018d08 <__csum_partial>
c04c004c: 4b b5 8c bd bl c0018d08 <__csum_partial>
c04c0368: 4b b5 89 a1 bl c0018d08 <__csum_partial>
c04c5254: 4b b5 3a b5 bl c0018d08 <__csum_partial>
c04c60d4: 4b b5 2c 35 bl c0018d08 <__csum_partial>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/checksum.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h
index 9cce06194dcc..cab8fec60005 100644
--- a/arch/powerpc/include/asm/checksum.h
+++ b/arch/powerpc/include/asm/checksum.h
@@ -164,7 +164,7 @@ static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
*/
__wsum __csum_partial(const void *buff, int len, __wsum sum);
-static inline __wsum csum_partial(const void *buff, int len, __wsum sum)
+static __always_inline __wsum csum_partial(const void *buff, int len, __wsum sum)
{
if (__builtin_constant_p(len) && len <= 16 && (len & 1) == 0) {
if (len == 2)
--
2.25.0
next reply other threads:[~2020-10-15 10:52 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-15 10:52 Christophe Leroy [this message]
2020-10-15 13:25 ` [PATCH] powerpc: force inlining of csum_partial() to avoid multiple csum_partial() with GCC10 Segher Boessenkool
2020-10-15 13:32 ` Christophe Leroy
2020-10-15 13:59 ` Christophe Leroy
2020-12-21 11:03 ` Michael Ellerman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=a1d31f84ddb0926813b17fcd5cc7f3fa7b4deac2.1602759123.git.christophe.leroy@csgroup.eu \
--to=christophe.leroy@csgroup.eu \
--cc=benh@kernel.crashing.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mpe@ellerman.id.au \
--cc=paulus@samba.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).