All of lore.kernel.org
 help / color / mirror / Atom feed
From: Anup Patel <apatel@ventanamicro.com>
To: Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Atish Patra <atishp@atishpatra.org>,
	Alistair Francis <Alistair.Francis@wdc.com>,
	Anup Patel <anup@brainfault.org>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	Anup Patel <apatel@ventanamicro.com>
Subject: [PATCH v2] RISC-V: Increase range and default value of NR_CPUS
Date: Sat, 19 Mar 2022 17:42:06 +0530	[thread overview]
Message-ID: <20220319121206.95919-1-apatel@ventanamicro.com> (raw)

Currently, the range and default value of NR_CPUS is too restrictive
for high-end RISC-V systems with large number of HARTs. The latest
QEMU virt machine supports upto 512 CPUs so the current NR_CPUS is
restrictive for QEMU as well. Other major architectures (such as
ARM64, x86_64, MIPS, etc) have a much higher range and default
value of NR_CPUS.

This patch increases NR_CPUS range to 2-512 and default value to
XLEN (i.e. 32 for RV32 and 64 for RV64).

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
Changes since v1:
 - Updated NR_CPUS range to 2-512 which reflects maximum number of
   CPUs supported by QEMU virt machine.
---
 arch/riscv/Kconfig | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 5adcbd9b5e88..423ac17f598c 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -274,10 +274,11 @@ config SMP
 	  If you don't know what to do here, say N.
 
 config NR_CPUS
-	int "Maximum number of CPUs (2-32)"
-	range 2 32
+	int "Maximum number of CPUs (2-512)"
+	range 2 512
 	depends on SMP
-	default "8"
+	default "32" if 32BIT
+	default "64" if 64BIT
 
 config HOTPLUG_CPU
 	bool "Support for hot-pluggable CPUs"
-- 
2.25.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

WARNING: multiple messages have this Message-ID (diff)
From: Anup Patel <apatel@ventanamicro.com>
To: Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Atish Patra <atishp@atishpatra.org>,
	Alistair Francis <Alistair.Francis@wdc.com>,
	Anup Patel <anup@brainfault.org>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	Anup Patel <apatel@ventanamicro.com>
Subject: [PATCH v2] RISC-V: Increase range and default value of NR_CPUS
Date: Sat, 19 Mar 2022 17:42:06 +0530	[thread overview]
Message-ID: <20220319121206.95919-1-apatel@ventanamicro.com> (raw)

Currently, the range and default value of NR_CPUS is too restrictive
for high-end RISC-V systems with large number of HARTs. The latest
QEMU virt machine supports upto 512 CPUs so the current NR_CPUS is
restrictive for QEMU as well. Other major architectures (such as
ARM64, x86_64, MIPS, etc) have a much higher range and default
value of NR_CPUS.

This patch increases NR_CPUS range to 2-512 and default value to
XLEN (i.e. 32 for RV32 and 64 for RV64).

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
Changes since v1:
 - Updated NR_CPUS range to 2-512 which reflects maximum number of
   CPUs supported by QEMU virt machine.
---
 arch/riscv/Kconfig | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 5adcbd9b5e88..423ac17f598c 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -274,10 +274,11 @@ config SMP
 	  If you don't know what to do here, say N.
 
 config NR_CPUS
-	int "Maximum number of CPUs (2-32)"
-	range 2 32
+	int "Maximum number of CPUs (2-512)"
+	range 2 512
 	depends on SMP
-	default "8"
+	default "32" if 32BIT
+	default "64" if 64BIT
 
 config HOTPLUG_CPU
 	bool "Support for hot-pluggable CPUs"
-- 
2.25.1


             reply	other threads:[~2022-03-19 12:12 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-19 12:12 Anup Patel [this message]
2022-03-19 12:12 ` [PATCH v2] RISC-V: Increase range and default value of NR_CPUS Anup Patel
2022-03-31 19:42 ` Palmer Dabbelt
2022-03-31 19:42   ` Palmer Dabbelt
2022-04-06  9:55   ` Heinrich Schuchardt
2022-04-06  9:55     ` Heinrich Schuchardt
2022-04-06 10:10     ` Anup Patel
2022-04-06 10:10       ` Anup Patel
2022-04-08 16:38       ` Heinrich Schuchardt
2022-04-08 16:38         ` Heinrich Schuchardt
2022-04-08 16:45         ` Anup Patel
2022-04-08 16:45           ` Anup Patel
2022-04-11 22:18           ` Atish Patra
2022-04-11 22:18             ` Atish Patra
2022-04-06 23:00     ` Atish Patra
2022-04-06 23:00       ` Atish Patra

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220319121206.95919-1-apatel@ventanamicro.com \
    --to=apatel@ventanamicro.com \
    --cc=Alistair.Francis@wdc.com \
    --cc=anup@brainfault.org \
    --cc=arnd@arndb.de \
    --cc=atishp@atishpatra.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=palmer@dabbelt.com \
    --cc=paul.walmsley@sifive.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.