forked from pool/s390-tools
53 lines
2.2 KiB
Diff
53 lines
2.2 KiB
Diff
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Subject: [PATCH] [BZ 192049] udev/dasd: change DASD udev-rule to set none scheduler
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From: Stefan Haberland <sth@linux.ibm.com>
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Description: dasd: change default scheduler to reduce CPU consumption
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Symptom: CPU consumption up to 20% higher for mq-deadline
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compared to none scheduler for DASD devices with no
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difference in throughput.
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Problem: Performance analysis showed that with recent DASD
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device drivers using multi-queue block queuing the
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throughput of mq-deadline and none scheduler is nearly
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identical but the CPU consumption of mq-deadline
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scheduler due to its optimizations is up to 20% higher
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compared to none scheduler.
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Solution: Set none scheduler as default in the DASD udev rule.
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Reproduction: Use DASD devices with mq-deadline scheduler.
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Upstream-ID: a65bc51cf4e5c1fe628bb182cc1a02ee83eb102d
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Problem-ID: 192049
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Upstream-Description:
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udev/dasd: change DASD udev-rule to set none scheduler
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Performance evaluation showed that using the mq-deadline scheduler for DASD
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devices leads to a significantly higher CPU consumption compared to using
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none scheduler while having the same amount of throughput.
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Setting none scheduler as default in the dasd udev rule.
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Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
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Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
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Signed-off-by: Jan Hoeppner <hoeppner@linux.ibm.com>
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Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
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---
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etc/udev/rules.d/59-dasd.rules | 8 ++++++++
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1 file changed, 8 insertions(+)
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--- a/etc/udev/rules.d/59-dasd.rules
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+++ b/etc/udev/rules.d/59-dasd.rules
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@@ -26,10 +26,10 @@
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LABEL="dasd_symlinks_end"
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-# on device add set request queue scheduler to deadline
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+# on device add set request queue scheduler to none
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SUBSYSTEM!="block", GOTO="sched_end"
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ACTION!="change", GOTO="sched_end"
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-KERNEL=="dasd*[!0-9]", TEST=="queue/scheduler", ATTR{queue/scheduler}="deadline"
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+KERNEL=="dasd*[!0-9]", TEST=="queue/scheduler", ATTR{queue/scheduler}="none"
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LABEL="sched_end"
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