2019-07-14 05:36:20

by Marcos Paulo de Souza

Subject: [PATCH 4/4] Documentation:kernel-per-CPU-kthreads.txt: Remove reference to elevator=

This argument was not being considered since blk-mq was set by default,
so removed this documentation to avoid confusion.

Signed-off-by: Marcos Paulo de Souza <[email protected]>
---
Documentation/kernel-per-CPU-kthreads.txt | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/Documentation/kernel-per-CPU-kthreads.txt b/Documentation/kernel-per-CPU-kthreads.txt
index 5623b9916411..c68c6c8c26a4 100644
--- a/Documentation/kernel-per-CPU-kthreads.txt
+++ b/Documentation/kernel-per-CPU-kthreads.txt
@@ -274,9 +274,7 @@ To reduce its OS jitter, do any of the following:
(based on an earlier one from Gilad Ben-Yossef) that
reduces or even eliminates vmstat overhead for some
workloads at https://lkml.org/lkml/2013/9/4/379.
- e. Boot with "elevator=noop" to avoid workqueue use by
- the block layer.
- f. If running on high-end powerpc servers, build with
+ e. If running on high-end powerpc servers, build with
CONFIG_PPC_RTAS_DAEMON=n. This prevents the RTAS
daemon from running on each CPU every second or so.
(This will require editing Kconfig files and will defeat
@@ -284,12 +282,12 @@ To reduce its OS jitter, do any of the following:
due to the rtas_event_scan() function.
WARNING: Please check your CPU specifications to
make sure that this is safe on your particular system.
- g. If running on Cell Processor, build your kernel with
+ f. If running on Cell Processor, build your kernel with
CBE_CPUFREQ_SPU_GOVERNOR=n to avoid OS jitter from
spu_gov_work().
WARNING: Please check your CPU specifications to
make sure that this is safe on your particular system.
- h. If running on PowerMAC, build your kernel with
+ g. If running on PowerMAC, build your kernel with
CONFIG_PMAC_RACKMETER=n to disable the CPU-meter,
avoiding OS jitter from rackmeter_do_timer().

--
2.22.0

2019-07-19 15:18:11

by Hannes Reinecke

Subject: Re: [PATCH 4/4] Documentation:kernel-per-CPU-kthreads.txt: Remove reference to elevator=

On 7/14/19 7:34 AM, Marcos Paulo de Souza wrote:
> This argument was not being considered since blk-mq was set by default,
> so removed this documentation to avoid confusion.
>
> Signed-off-by: Marcos Paulo de Souza <[email protected]>
> ---
> Documentation/kernel-per-CPU-kthreads.txt | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
Reviewed-by: Hannes Reinecke <[email protected]>

Cheers,

Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
[email protected] +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah
HRB 21284 (AG Nürnberg)