Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 28 May 2019 10:47:51 -0700 (PDT)
Subject:     Re: [PATCH] RISC-V: defconfig: Enable NO_HZ_IDLE and HIGH_RES_TIMERS
In-Reply-To: <CAAhSdy3GqjS06QxCtY6OUkBZds4gygQsAkaoaa+sMj3z6qgUBQ@mail.gmail.com>
CC:     Anup Patel <Anup.Patel@wdc.com>, aou@eecs.berkeley.edu,
        Atish Patra <Atish.Patra@wdc.com>,
        Christoph Hellwig <hch@infradead.org>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
From:   Palmer Dabbelt <palmer@sifive.com>
To:     anup@brainfault.org, Paul Walmsley <paul.walmsley@sifive.com>
Message-ID: <mhng-2b0ca072-2d6d-4422-96a2-2a4254255cc6@palmer-si-x1e>
Mime-Version: 1.0 (MHng)
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, 20 May 2019 01:05:22 PDT (-0700), anup@brainfault.org wrote:
> On Wed, May 15, 2019 at 12:00 PM Anup Patel <Anup.Patel@wdc.com> wrote:
>>
>> This patch enables NO_HZ_IDLE (idle dynamic ticks) and HIGH_RES_TIMERS
>> (hrtimers) in RV32 and RV64 defconfigs.
>>
>> Both of the above options are enabled by default for architectures
>> such as x86, ARM, and ARM64.
>>
>> The idle dynamic ticks helps use save power by stopping timer ticks
>> when the system is idle whereas hrtimers is a much improved timer
>> subsystem compared to the old "timer wheel" based system.
>>
>> This patch is tested on SiFive Unleashed board and QEMU Virt machine.
>>
>> Signed-off-by: Anup Patel <anup.patel@wdc.com>
>> ---
>>  arch/riscv/configs/defconfig      | 2 ++
>>  arch/riscv/configs/rv32_defconfig | 2 ++
>>  2 files changed, 4 insertions(+)
>>
>> diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig
>> index 2fd3461e50ab..f254c352ec57 100644
>> --- a/arch/riscv/configs/defconfig
>> +++ b/arch/riscv/configs/defconfig
>> @@ -1,5 +1,7 @@
>>  CONFIG_SYSVIPC=y
>>  CONFIG_POSIX_MQUEUE=y
>> +CONFIG_NO_HZ_IDLE=y
>> +CONFIG_HIGH_RES_TIMERS=y
>>  CONFIG_IKCONFIG=y
>>  CONFIG_IKCONFIG_PROC=y
>>  CONFIG_CGROUPS=y
>> diff --git a/arch/riscv/configs/rv32_defconfig b/arch/riscv/configs/rv32_defconfig
>> index 1a911ed8e772..d5449ef805a3 100644
>> --- a/arch/riscv/configs/rv32_defconfig
>> +++ b/arch/riscv/configs/rv32_defconfig
>> @@ -1,5 +1,7 @@
>>  CONFIG_SYSVIPC=y
>>  CONFIG_POSIX_MQUEUE=y
>> +CONFIG_NO_HZ_IDLE=y
>> +CONFIG_HIGH_RES_TIMERS=y
>>  CONFIG_IKCONFIG=y
>>  CONFIG_IKCONFIG_PROC=y
>>  CONFIG_CGROUPS=y
>> --
>> 2.17.1
>>
>
> Hi All,
>
> Any comments on this one?
>
> @Palmer, It would be nice to have this in Linux-5.2

My only issue here is testing: IIRC last time we tried this it ended up causing
trouble.  I'm in the process of switching to Yocto right now for my tests, so
it'll be a bit slow.