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s390-tools/s390-tools-sles15sp3-dasd-change-DASD-udev-rule-to-set-none-scheduler.patch
Mark Post 02084eb837 Accepting request 885467 from home:markkp:branches:Base:System
- Added s390-tools-sles15sp3-dasd-change-DASD-udev-rule-to-set-none-scheduler.patch
  dasd: change default scheduler to reduce CPU consumption (bsc#1183810)
- Modified s390-tools-sles12-create-filesystem-links.patch to fit after
  applying s390-tools-sles15sp3-dasd-change-DASD-udev-rule-to-set-none-scheduler.patch
- Removed 59-dasd.rules-wait_for.patch obsoleted by bsc#1183810.

OBS-URL: https://build.opensuse.org/request/show/885467
OBS-URL: https://build.opensuse.org/package/show/Base:System/s390-tools?expand=0&rev=116
2021-04-14 20:07:00 +00:00

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2.2 KiB
Diff

Subject: [PATCH] [BZ 192049] udev/dasd: change DASD udev-rule to set none scheduler
From: Stefan Haberland <sth@linux.ibm.com>
Description: dasd: change default scheduler to reduce CPU consumption
Symptom: CPU consumption up to 20% higher for mq-deadline
compared to none scheduler for DASD devices with no
difference in throughput.
Problem: Performance analysis showed that with recent DASD
device drivers using multi-queue block queuing the
throughput of mq-deadline and none scheduler is nearly
identical but the CPU consumption of mq-deadline
scheduler due to its optimizations is up to 20% higher
compared to none scheduler.
Solution: Set none scheduler as default in the DASD udev rule.
Reproduction: Use DASD devices with mq-deadline scheduler.
Upstream-ID: a65bc51cf4e5c1fe628bb182cc1a02ee83eb102d
Problem-ID: 192049
Upstream-Description:
udev/dasd: change DASD udev-rule to set none scheduler
Performance evaluation showed that using the mq-deadline scheduler for DASD
devices leads to a significantly higher CPU consumption compared to using
none scheduler while having the same amount of throughput.
Setting none scheduler as default in the dasd udev rule.
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Signed-off-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
---
etc/udev/rules.d/59-dasd.rules | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/etc/udev/rules.d/59-dasd.rules
+++ b/etc/udev/rules.d/59-dasd.rules
@@ -26,10 +26,10 @@
LABEL="dasd_symlinks_end"
-# on device add set request queue scheduler to deadline
+# on device add set request queue scheduler to none
SUBSYSTEM!="block", GOTO="sched_end"
ACTION!="change", GOTO="sched_end"
-KERNEL=="dasd*[!0-9]", TEST=="queue/scheduler", ATTR{queue/scheduler}="deadline"
+KERNEL=="dasd*[!0-9]", TEST=="queue/scheduler", ATTR{queue/scheduler}="none"
LABEL="sched_end"