From: Lukasz Luba <l.luba@partner.samsung.com>
To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Cc: l.luba@partner.samsung.com, b.zolnierkie@samsung.com,
linux@armlinux.org.uk
Subject: [PATCH] config: arm: moxart: remove PROVE_LOCKING from defconfig
Date: Tue, 9 Oct 2018 17:36:58 +0200 [thread overview]
Message-ID: <20181009153711eucas1p29688c4724f8b9d81a3096dd97a363083~b_scuHGMD0310103101eucas1p2i@eucas1p2.samsung.com> (raw)
In-Reply-To: CGME20181009153711eucas1p29688c4724f8b9d81a3096dd97a363083@eucas1p2.samsung.com
PROVE_LOCKING enables LOCKDEP, which causes big overhead on cache and
bus transactions.
On some ARM big.LITTLE architecutres (Exynos 5433) the overhead is really big.
The overhead can be measures using hackbench which will speed up
by x3 times (11sec -> 3.4sec).
When you check transaction on cache or buses, the results are way higher
than normal for the same hackbench test:
L1d cache invalidations: 26mln vs 4mln
L2u cache invalidations: 42mln vs 12mln
bus cyc/access: 30cyc/access vs. 20cyc/access
context switch is x3 times cheaper
Enable this option only when you have some locking issue to investigate.
Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>
---
arch/arm/configs/moxart_defconfig | 1 -
1 file changed, 1 deletion(-)
diff --git a/arch/arm/configs/moxart_defconfig b/arch/arm/configs/moxart_defconfig
index 2da0d9e..5740d47 100644
--- a/arch/arm/configs/moxart_defconfig
+++ b/arch/arm/configs/moxart_defconfig
@@ -136,7 +136,6 @@ CONFIG_DEBUG_SHIRQ=y
CONFIG_DETECT_HUNG_TASK=y
# CONFIG_SCHED_DEBUG is not set
# CONFIG_DEBUG_PREEMPT is not set
-CONFIG_PROVE_LOCKING=y
CONFIG_DMA_API_DEBUG=y
CONFIG_KGDB=y
CONFIG_DEBUG_LL=y
--
2.7.4
parent reply other threads:[~2018-10-09 15:37 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <CGME20181009153711eucas1p29688c4724f8b9d81a3096dd97a363083@eucas1p2.samsung.com>]
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='20181009153711eucas1p29688c4724f8b9d81a3096dd97a363083~b_scuHGMD0310103101eucas1p2i@eucas1p2.samsung.com' \
--to=l.luba@partner.samsung.com \
--cc=b.zolnierkie@samsung.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@armlinux.org.uk \
/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).