Re: [PATCH 07/10] ARC: [plat-eznps] disabled stall counter due to a HW bug

From	Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 07/10] ARC: [plat-eznps] disabled stall counter due to a HW bug
Date	2017-05-25 13:20 +0200
Message-ID	<tKYY9-7sN-1@gated-at.bofh.it> (permalink)
References	<tKQQV-2dF-7@gated-at.bofh.it> <tKQQV-2dF-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Hi Noam,

On Thu, 2017-05-25 at 05:34 +0300, Noam Camus wrote:
> From: Noam Camus <noamca@mellanox.com>
> 
> This counter represents threshold for consecutive stall that which
> trigger HW threads scheduling.
> Low values of this counter cause downgrade in performance
> and in the worst case even a livelock.
> 
> Signed-off-by: Noam Camus <noamca@mellanox.com>
> ---
>  arch/arc/plat-eznps/mtm.c |    2 --
>  1 files changed, 0 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arc/plat-eznps/mtm.c b/arch/arc/plat-eznps/mtm.c
> index aaaaffd..e0cb36b 100644
> --- a/arch/arc/plat-eznps/mtm.c
> +++ b/arch/arc/plat-eznps/mtm.c
> @@ -119,8 +119,6 @@ void mtm_enable_core(unsigned int cpu)
>  	mt_ctrl.value = 0;
>  	mt_ctrl.hsen = 1;
>  	mt_ctrl.hs_cnt = MT_CTRL_HS_CNT;
> -	mt_ctrl.sten = 1;
> -	mt_ctrl.st_cnt = MT_CTRL_ST_CNT;

Even though I don't know your architecture this change doesn't
make enough sense to me in absence of better explanation of what is
really done here.

I.e. how removal of those 2 lines above improve your situation.

-Alexey

Thread

[PATCH 07/10] ARC: [plat-eznps] disabled stall counter due to a HW bug Noam Camus <noamca@mellanox.com> - 2017-05-25 04:40 +0200
  Re: [PATCH 07/10] ARC: [plat-eznps] disabled stall counter due to a  HW bug Alexey Brodkin <Alexey.Brodkin@synopsys.com> - 2017-05-25 13:20 +0200
    RE: [PATCH 07/10] ARC: [plat-eznps] disabled stall counter due to a  HW bug Noam Camus <noamca@mellanox.com> - 2017-05-25 13:20 +0200

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