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[109.243.64.225]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-acaa1ccd255sm910312666b.156.2025.04.14.07.50.33 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 14 Apr 2025 07:50:33 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: d24a5b25-193f-11f0-9eae-5ba50f476ded DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1744642234; x=1745247034; darn=lists.xenproject.org; h=in-reply-to:from:content-language:references:cc:to:subject :user-agent:mime-version:date:message-id:from:to:cc:subject:date :message-id:reply-to; bh=ssKW7qnqudOt5C98+v8q6rM8aAHHrH+UyYnvLLgTX8U=; b=SbWA9Ty7U8IcCD1AUu0jsRXtEjPVKlIjV0pV2VNvfCVzDNkJih0FsHAVH8bm9p+ksI X3R6FtBJDvP24wmhqLrvgfeHZYYkCFMso5QwDZ1nhMx2iLnJMcUCh73HiNWdeQlazYi1 Un78xquxEJeypb3RaNn7COKDjXOXYSeYIc4jwJDY8BTFXMInytNqz65uADRYgHO4o61v ueEsRpOUE8k7C0fSvFNdKcBCYtylk8bnykzDFjVRV3qj6QY0EbQFZjJLoXsch1JLEtnP GeRBht1YgopsDWOdnA3CIez4F6xgpp6NK/J3yzR2WMcnJq1F1ftQ8l6xkKGOs+Y2n/1S k4wA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1744642234; x=1745247034; h=in-reply-to:from:content-language:references:cc:to:subject :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=ssKW7qnqudOt5C98+v8q6rM8aAHHrH+UyYnvLLgTX8U=; b=OwmnD6KlWUmhFuvUX+DxQMdnfamI2b/QUEQmfuRdkjPsY6BihzD/VkvZSaG+ZNiCC7 BUud/hTEQPc3khkAY3oK7StJHcepd/AczSQTbxbCGy7EPENpa9fusS0D4FAbLfZsLPA2 n5UTCrVGODPNqhZelvUYatLOVQxR4ilTfumzRMLdpPk8+csipbK7c8fraL5OFDohMDn6 jxQw7+Wv4cCLRcyVbZtrQq4k6LsZsYPy4ETIEbQAcXeMRo2Odct51Ph3tEXrSux+IlVI 2KVnbeYd9RIen7toLEzEgB5sYs4ny8TafknarFq70KpOrjm1Yd6VEhiIAVxksfY7mMr7 pNSw== X-Forwarded-Encrypted: i=1; AJvYcCW+InS63g2DwXpzUZexX1IqUYBpDb/Qb3vxhUNkuJ3j2reszi5mP3OM3/IDHimwga20KxRsJtrJ5fE=@lists.xenproject.org X-Gm-Message-State: AOJu0YyWzm+U4AUA+fqlzMQrO37sn1VzYNYdf4A4G21of+DVLhZsE00T whDteyiiEmYUYcvaXVt7TclEKewS0vyrKCpXGeIstp1ZDoErMQN5 X-Gm-Gg: ASbGnctyMLHVhTQKUzcMdcdg8tr76dCky6KCtPWm1v/+k71XbSSride2/DhCSduofe8 U33UN1wFCSoenjSNGOquACn0tGqpqSbpzYbQUv33gyHUEKj9laN1BCZA/vJ2q1X2cr76rZiITvW T9zsC7RIgXQZRC3xaGZ7Oay33KKUO87fygQ4ZFwRFTjEzXFbQbPNVkdTXxGOBTGXHqXxOEcWWGW Rq20DU4XZKJZoP+FaFgALZZaCcU0iEZONMjrKM7kLSjg3Cz/do97nu6KgZznvf0nZp2u3FrgG23 e63KvIsYRXnXDdachdufYZhPHrBovFva8qkkQ6RNEVdfhfB3yc9klfjUBwjmlEWfcsRIIBYxfNv rgA6HI36LaJoE2cr5 X-Google-Smtp-Source: AGHT+IGtmczYQE2lLO/Swp2K6JUtF5S6Nrpq2iEg9+A5Yci3N77obqbyzsh9pHd7VA9g4kSe773q1g== X-Received: by 2002:a17:907:3d0e:b0:ac7:ec75:c65b with SMTP id a640c23a62f3a-acad34dd659mr1171271866b.36.1744642234150; Mon, 14 Apr 2025 07:50:34 -0700 (PDT) Content-Type: multipart/alternative; boundary="------------yo4C76a0szgaZfAxZHH92FIz" Message-ID: Date: Mon, 14 Apr 2025 16:50:33 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 01/14] xen/riscv: implement get_s_time() To: Jan Beulich Cc: Alistair Francis , Bob Eshleman , Connor Davis , Andrew Cooper , Anthony PERARD , Michal Orzel , Julien Grall , =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= , Stefano Stabellini , xen-devel@lists.xenproject.org References: <7f26a9cb-a685-4a2a-a470-8c5e94ddc31e@suse.com> Content-Language: en-US From: Oleksii Kurochko In-Reply-To: <7f26a9cb-a685-4a2a-a470-8c5e94ddc31e@suse.com> This is a multi-part message in MIME format. --------------yo4C76a0szgaZfAxZHH92FIz Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 4/10/25 2:52 PM, Jan Beulich wrote: > On 08.04.2025 17:57, Oleksii Kurochko wrote: >> @@ -23,6 +24,11 @@ static inline cycles_t get_cycles(void) >> return csr_read(CSR_TIME); >> } >> >> +static inline s_time_t ticks_to_ns(uint64_t ticks) >> +{ >> + return muldiv64(ticks, SECONDS(1), 1000 * cpu_khz); >> +} > Why the extra multiplication by 1000? I.e. why not > "muldiv64(ticks, MILLISECONDS(1), cpu_khz)", getting away with just one > multiplication and a reduced risk of encountering intermediate overflow > (affecting only hypothetical above 4THz CPUs then)? Multiplication by 1000 was needed to convert khz to hz, but yes, your option would be better. > >> --- a/xen/arch/riscv/time.c >> +++ b/xen/arch/riscv/time.c >> @@ -4,10 +4,17 @@ >> #include >> #include >> #include >> +#include >> >> unsigned long __ro_after_init cpu_khz; /* CPU clock frequency in kHz. */ >> uint64_t __ro_after_init boot_clock_cycles; >> >> +s_time_t get_s_time(void) >> +{ >> + uint64_t ticks = get_cycles() - boot_clock_cycles; >> + return ticks_to_ns(ticks); > Nit: Blank line between declaration(s) and statement(s) please, as well as > ahead of the main "return" of a function. > > Happy to make both adjustments upon committing, so long as you agree; then: > Reviewed-by: Jan Beulich I'll be happy with that. Thank you very much. ~ Oleksii --------------yo4C76a0szgaZfAxZHH92FIz Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 7bit


On 4/10/25 2:52 PM, Jan Beulich wrote:
On 08.04.2025 17:57, Oleksii Kurochko wrote:

@@ -23,6 +24,11 @@ static inline cycles_t get_cycles(void)
     return csr_read(CSR_TIME);
 }
 
+static inline s_time_t ticks_to_ns(uint64_t ticks)
+{
+    return muldiv64(ticks, SECONDS(1), 1000 * cpu_khz);
+}

Why the extra multiplication by 1000? I.e. why not
"muldiv64(ticks, MILLISECONDS(1), cpu_khz)", getting away with just one
multiplication and a reduced risk of encountering intermediate overflow
(affecting only hypothetical above 4THz CPUs then)?
Multiplication by 1000 was needed to convert khz to hz, but yes, your option
would be better.




--- a/xen/arch/riscv/time.c
+++ b/xen/arch/riscv/time.c
@@ -4,10 +4,17 @@
 #include <xen/init.h>
 #include <xen/lib.h>
 #include <xen/sections.h>
+#include <xen/types.h>
 
 unsigned long __ro_after_init cpu_khz; /* CPU clock frequency in kHz. */
 uint64_t __ro_after_init boot_clock_cycles;
 
+s_time_t get_s_time(void)
+{
+    uint64_t ticks = get_cycles() - boot_clock_cycles;
+    return ticks_to_ns(ticks);

Nit: Blank line between declaration(s) and statement(s) please, as well as
ahead of the main "return" of a function.

Happy to make both adjustments upon committing, so long as you agree; then:
Reviewed-by: Jan Beulich <jbeulich@suse.com>
I'll be happy with that.

Thank you very much.

~ Oleksii
--------------yo4C76a0szgaZfAxZHH92FIz--