[PATCH v2] ipvs: increase ip_vs_conn_tab_bits range for 64BIT

[PATCH v2] ipvs: increase ip_vs_conn_tab_bits range for 64BIT

[Abhijeet Rastogi]

Current range [8, 20] is set purely due to historical reasons
because at the time, ~1M (2^20) was considered sufficient.
With this change, 27 is the upper limit for 64-bit, 20 otherwise.

Previous change regarding this limit is here.

Link: https://lore.kernel.org/all/86eabeb9dd62aebf1e2533926fdd13fed48bab1f.1631289960.git.aclaudi@redhat.com/T/#u

Signed-off-by: Abhijeet Rastogi <abhijeet.1989@gmail.com>
---
The conversation for this started at: 

https://www.spinics.net/lists/netfilter/msg60995.html

The upper limit for algo is any bit size less than 32, so this
change will allow us to set bit size > 20. Today, it is common to have
RAM available to handle greater than 2^20 connections per-host.

Distros like RHEL already allow setting limits higher than 20.
---
Changes in v2:
- Lower the ranges, 27 for 64bit, 20 otherwise
- Link to v1: https://lore.kernel.org/r/20230412-increase_ipvs_conn_tab_bits-v1-1-60a4f9f4c8f2@gmail.com
---
 net/netfilter/ipvs/Kconfig      | 26 +++++++++++++-------------
 net/netfilter/ipvs/ip_vs_conn.c |  4 ++--
 2 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/net/netfilter/ipvs/Kconfig b/net/netfilter/ipvs/Kconfig
index 271da8447b29..aac5d6bd82e6 100644
--- a/net/netfilter/ipvs/Kconfig
+++ b/net/netfilter/ipvs/Kconfig
@@ -44,7 +44,8 @@ config	IP_VS_DEBUG
 
 config	IP_VS_TAB_BITS
 	int "IPVS connection table size (the Nth power of 2)"
-	range 8 20
+	range 8 20 if !64BIT
+	range 8 27 if 64BIT
 	default 12
 	help
 	  The IPVS connection hash table uses the chaining scheme to handle
@@ -52,18 +53,17 @@ config	IP_VS_TAB_BITS
 	  reduce conflicts when there are hundreds of thousands of connections
 	  in the hash table.
 
-	  Note the table size must be power of 2. The table size will be the
-	  value of 2 to the your input number power. The number to choose is
-	  from 8 to 20, the default number is 12, which means the table size
-	  is 4096. Don't input the number too small, otherwise you will lose
-	  performance on it. You can adapt the table size yourself, according
-	  to your virtual server application. It is good to set the table size
-	  not far less than the number of connections per second multiplying
-	  average lasting time of connection in the table.  For example, your
-	  virtual server gets 200 connections per second, the connection lasts
-	  for 200 seconds in average in the connection table, the table size
-	  should be not far less than 200x200, it is good to set the table
-	  size 32768 (2**15).
+	  Note the table size must be power of 2. The table size will be the value
+	  of 2 to the your input number power. The number to choose is from 8 to 27
+	  for 64BIT(20 otherwise), the default number is 12, which means the table
+	  size is 4096. Don't input the number too small, otherwise you will lose
+	  performance on it. You can adapt the table size yourself, according to
+	  your virtual server application. It is good to set the table size not far
+	  less than the number of connections per second multiplying average lasting
+	  time of connection in the table.  For example, your virtual server gets
+	  200 connections per second, the connection lasts for 200 seconds in
+	  average in the connection table, the table size should be not far less
+	  than 200x200, it is good to set the table size 32768 (2**15).
 
 	  Another note that each connection occupies 128 bytes effectively and
 	  each hash entry uses 8 bytes, so you can estimate how much memory is
diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c
index 13534e02346c..e1b9b52909a5 100644
--- a/net/netfilter/ipvs/ip_vs_conn.c
+++ b/net/netfilter/ipvs/ip_vs_conn.c
@@ -1484,8 +1484,8 @@ int __init ip_vs_conn_init(void)
 	int idx;
 
 	/* Compute size and mask */
-	if (ip_vs_conn_tab_bits < 8 || ip_vs_conn_tab_bits > 20) {
-		pr_info("conn_tab_bits not in [8, 20]. Using default value\n");
+	if (ip_vs_conn_tab_bits < 8 || ip_vs_conn_tab_bits > 27) {
+		pr_info("conn_tab_bits not in [8, 27]. Using default value\n");
 		ip_vs_conn_tab_bits = CONFIG_IP_VS_TAB_BITS;
 	}
 	ip_vs_conn_tab_size = 1 << ip_vs_conn_tab_bits;

---
base-commit: 09a9639e56c01c7a00d6c0ca63f4c7c41abe075d
change-id: 20230412-increase_ipvs_conn_tab_bits-4322c90da216

Best regards,
-- 
Abhijeet Rastogi <abhijeet.1989@gmail.com>

Re: [PATCH v2] ipvs: increase ip_vs_conn_tab_bits range for 64BIT

[Julian Anastasov]

	Hello,

On Sun, 14 May 2023, Abhijeet Rastogi wrote:

> Current range [8, 20] is set purely due to historical reasons
> because at the time, ~1M (2^20) was considered sufficient.
> With this change, 27 is the upper limit for 64-bit, 20 otherwise.
> 
> Previous change regarding this limit is here.
> 
> Link: https://lore.kernel.org/all/86eabeb9dd62aebf1e2533926fdd13fed48bab1f.1631289960.git.aclaudi@redhat.com/T/#u
> 
> Signed-off-by: Abhijeet Rastogi <abhijeet.1989@gmail.com>
> ---
> The conversation for this started at: 
> 
> https://www.spinics.net/lists/netfilter/msg60995.html
> 
> The upper limit for algo is any bit size less than 32, so this
> change will allow us to set bit size > 20. Today, it is common to have
> RAM available to handle greater than 2^20 connections per-host.
> 
> Distros like RHEL already allow setting limits higher than 20.
> ---
> Changes in v2:
> - Lower the ranges, 27 for 64bit, 20 otherwise
> - Link to v1: https://lore.kernel.org/r/20230412-increase_ipvs_conn_tab_bits-v1-1-60a4f9f4c8f2@gmail.com
> ---
>  net/netfilter/ipvs/Kconfig      | 26 +++++++++++++-------------
>  net/netfilter/ipvs/ip_vs_conn.c |  4 ++--
>  2 files changed, 15 insertions(+), 15 deletions(-)
> 
> diff --git a/net/netfilter/ipvs/Kconfig b/net/netfilter/ipvs/Kconfig
> index 271da8447b29..aac5d6bd82e6 100644
> --- a/net/netfilter/ipvs/Kconfig
> +++ b/net/netfilter/ipvs/Kconfig
> @@ -44,7 +44,8 @@ config	IP_VS_DEBUG
>  
>  config	IP_VS_TAB_BITS
>  	int "IPVS connection table size (the Nth power of 2)"
> -	range 8 20
> +	range 8 20 if !64BIT
> +	range 8 27 if 64BIT
>  	default 12
>  	help
>  	  The IPVS connection hash table uses the chaining scheme to handle
> @@ -52,18 +53,17 @@ config	IP_VS_TAB_BITS
>  	  reduce conflicts when there are hundreds of thousands of connections
>  	  in the hash table.
>  
> -	  Note the table size must be power of 2. The table size will be the
> -	  value of 2 to the your input number power. The number to choose is
> -	  from 8 to 20, the default number is 12, which means the table size
> -	  is 4096. Don't input the number too small, otherwise you will lose
> -	  performance on it. You can adapt the table size yourself, according
> -	  to your virtual server application. It is good to set the table size
> -	  not far less than the number of connections per second multiplying
> -	  average lasting time of connection in the table.  For example, your
> -	  virtual server gets 200 connections per second, the connection lasts
> -	  for 200 seconds in average in the connection table, the table size
> -	  should be not far less than 200x200, it is good to set the table
> -	  size 32768 (2**15).
> +	  Note the table size must be power of 2. The table size will be the value
> +	  of 2 to the your input number power. The number to choose is from 8 to 27
> +	  for 64BIT(20 otherwise), the default number is 12, which means the table
> +	  size is 4096. Don't input the number too small, otherwise you will lose
> +	  performance on it. You can adapt the table size yourself, according to
> +	  your virtual server application. It is good to set the table size not far
> +	  less than the number of connections per second multiplying average lasting
> +	  time of connection in the table.  For example, your virtual server gets
> +	  200 connections per second, the connection lasts for 200 seconds in
> +	  average in the connection table, the table size should be not far less
> +	  than 200x200, it is good to set the table size 32768 (2**15).

	Can you keep the previous line width of the above help
because on standard 80-width window the help now gets truncated in
make menuconfig.

	After that I'll send a patch on top of yours to limit the
rows depending on the memory.

>  	  Another note that each connection occupies 128 bytes effectively and
>  	  each hash entry uses 8 bytes, so you can estimate how much memory is
> diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c
> index 13534e02346c..e1b9b52909a5 100644
> --- a/net/netfilter/ipvs/ip_vs_conn.c
> +++ b/net/netfilter/ipvs/ip_vs_conn.c
> @@ -1484,8 +1484,8 @@ int __init ip_vs_conn_init(void)
>  	int idx;
>  
>  	/* Compute size and mask */
> -	if (ip_vs_conn_tab_bits < 8 || ip_vs_conn_tab_bits > 20) {
> -		pr_info("conn_tab_bits not in [8, 20]. Using default value\n");
> +	if (ip_vs_conn_tab_bits < 8 || ip_vs_conn_tab_bits > 27) {
> +		pr_info("conn_tab_bits not in [8, 27]. Using default value\n");
>  		ip_vs_conn_tab_bits = CONFIG_IP_VS_TAB_BITS;
>  	}
>  	ip_vs_conn_tab_size = 1 << ip_vs_conn_tab_bits;
> 
> ---

Regards

--
Julian Anastasov <ja@ssi.bg>

Re: [PATCH v2] ipvs: increase ip_vs_conn_tab_bits range for 64BIT

[Abhijeet Rastogi]

Hi Julian Anastasov,

>Can you keep the previous line width of the above help
because on standard 80-width window the help now gets truncated in
make menuconfig.

Refer this screenshot: https://i.imgur.com/9LgttpC.png

Sorry for the confusion, I was already expecting this comment. The
patch had a few words added, hence it feels like many lines have
changed. However, no line actually exceeds 80 width.

Longest line is still 80-width max. Do you prefer I reduce it to a
lower number like 70?

Thanks,
Abhijeet


On Mon, May 15, 2023 at 8:18 AM Julian Anastasov <ja@ssi.bg> wrote:
>
>
>         Hello,
>
> On Sun, 14 May 2023, Abhijeet Rastogi wrote:
>
> > Current range [8, 20] is set purely due to historical reasons
> > because at the time, ~1M (2^20) was considered sufficient.
> > With this change, 27 is the upper limit for 64-bit, 20 otherwise.
> >
> > Previous change regarding this limit is here.
> >
> > Link: https://lore.kernel.org/all/86eabeb9dd62aebf1e2533926fdd13fed48bab1f.1631289960.git.aclaudi@redhat.com/T/#u
> >
> > Signed-off-by: Abhijeet Rastogi <abhijeet.1989@gmail.com>
> > ---
> > The conversation for this started at:
> >
> > https://www.spinics.net/lists/netfilter/msg60995.html
> >
> > The upper limit for algo is any bit size less than 32, so this
> > change will allow us to set bit size > 20. Today, it is common to have
> > RAM available to handle greater than 2^20 connections per-host.
> >
> > Distros like RHEL already allow setting limits higher than 20.
> > ---
> > Changes in v2:
> > - Lower the ranges, 27 for 64bit, 20 otherwise
> > - Link to v1: https://lore.kernel.org/r/20230412-increase_ipvs_conn_tab_bits-v1-1-60a4f9f4c8f2@gmail.com
> > ---
> >  net/netfilter/ipvs/Kconfig      | 26 +++++++++++++-------------
> >  net/netfilter/ipvs/ip_vs_conn.c |  4 ++--
> >  2 files changed, 15 insertions(+), 15 deletions(-)
> >
> > diff --git a/net/netfilter/ipvs/Kconfig b/net/netfilter/ipvs/Kconfig
> > index 271da8447b29..aac5d6bd82e6 100644
> > --- a/net/netfilter/ipvs/Kconfig
> > +++ b/net/netfilter/ipvs/Kconfig
> > @@ -44,7 +44,8 @@ config      IP_VS_DEBUG
> >
> >  config       IP_VS_TAB_BITS
> >       int "IPVS connection table size (the Nth power of 2)"
> > -     range 8 20
> > +     range 8 20 if !64BIT
> > +     range 8 27 if 64BIT
> >       default 12
> >       help
> >         The IPVS connection hash table uses the chaining scheme to handle
> > @@ -52,18 +53,17 @@ config    IP_VS_TAB_BITS
> >         reduce conflicts when there are hundreds of thousands of connections
> >         in the hash table.
> >
> > -       Note the table size must be power of 2. The table size will be the
> > -       value of 2 to the your input number power. The number to choose is
> > -       from 8 to 20, the default number is 12, which means the table size
> > -       is 4096. Don't input the number too small, otherwise you will lose
> > -       performance on it. You can adapt the table size yourself, according
> > -       to your virtual server application. It is good to set the table size
> > -       not far less than the number of connections per second multiplying
> > -       average lasting time of connection in the table.  For example, your
> > -       virtual server gets 200 connections per second, the connection lasts
> > -       for 200 seconds in average in the connection table, the table size
> > -       should be not far less than 200x200, it is good to set the table
> > -       size 32768 (2**15).
> > +       Note the table size must be power of 2. The table size will be the value
> > +       of 2 to the your input number power. The number to choose is from 8 to 27
> > +       for 64BIT(20 otherwise), the default number is 12, which means the table
> > +       size is 4096. Don't input the number too small, otherwise you will lose
> > +       performance on it. You can adapt the table size yourself, according to
> > +       your virtual server application. It is good to set the table size not far
> > +       less than the number of connections per second multiplying average lasting
> > +       time of connection in the table.  For example, your virtual server gets
> > +       200 connections per second, the connection lasts for 200 seconds in
> > +       average in the connection table, the table size should be not far less
> > +       than 200x200, it is good to set the table size 32768 (2**15).
>
>         Can you keep the previous line width of the above help
> because on standard 80-width window the help now gets truncated in
> make menuconfig.
>
>         After that I'll send a patch on top of yours to limit the
> rows depending on the memory.
>
> >         Another note that each connection occupies 128 bytes effectively and
> >         each hash entry uses 8 bytes, so you can estimate how much memory is
> > diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c
> > index 13534e02346c..e1b9b52909a5 100644
> > --- a/net/netfilter/ipvs/ip_vs_conn.c
> > +++ b/net/netfilter/ipvs/ip_vs_conn.c
> > @@ -1484,8 +1484,8 @@ int __init ip_vs_conn_init(void)
> >       int idx;
> >
> >       /* Compute size and mask */
> > -     if (ip_vs_conn_tab_bits < 8 || ip_vs_conn_tab_bits > 20) {
> > -             pr_info("conn_tab_bits not in [8, 20]. Using default value\n");
> > +     if (ip_vs_conn_tab_bits < 8 || ip_vs_conn_tab_bits > 27) {
> > +             pr_info("conn_tab_bits not in [8, 27]. Using default value\n");
> >               ip_vs_conn_tab_bits = CONFIG_IP_VS_TAB_BITS;
> >       }
> >       ip_vs_conn_tab_size = 1 << ip_vs_conn_tab_bits;
> >
> > ---
>
> Regards
>
> --
> Julian Anastasov <ja@ssi.bg>
>


--
Cheers,
Abhijeet (https://abhi.host)

Re: [PATCH v2] ipvs: increase ip_vs_conn_tab_bits range for 64BIT

[Julian Anastasov]

	Hello,

On Mon, 15 May 2023, Abhijeet Rastogi wrote:

> Hi Julian Anastasov,
> 
> >Can you keep the previous line width of the above help
> because on standard 80-width window the help now gets truncated in
> make menuconfig.
> 
> Refer this screenshot: https://i.imgur.com/9LgttpC.png
> 
> Sorry for the confusion, I was already expecting this comment. The
> patch had a few words added, hence it feels like many lines have
> changed. However, no line actually exceeds 80 width.
> 
> Longest line is still 80-width max. Do you prefer I reduce it to a
> lower number like 70?

	I'm checking in menuconfig where the help text is displayed.
The word "lasting" is visible up to "last". So, 3 columns are not
visible. In editor, this line is 84, may be up to 80 should be good.
You are using editor that represents Tabs as 4 spaces, that is why
it looks like it fits in 80. Open Kconfig in less. But in editor/less
does not matter because menuconfig simply ignores the leading spaces
in Kconfig and considers the text length which should be no more
than 70.

Regards

--
Julian Anastasov <ja@ssi.bg>

Re: [PATCH v2] ipvs: increase ip_vs_conn_tab_bits range for 64BIT

[Abhijeet Rastogi]

@Julian, Thank you for the clarification. I've sent v3 and I truly
appreciate your patience with this.

On Mon, May 15, 2023 at 10:35 PM Julian Anastasov <ja@ssi.bg> wrote:
>
>
>         Hello,
>
> On Mon, 15 May 2023, Abhijeet Rastogi wrote:
>
> > Hi Julian Anastasov,
> >
> > >Can you keep the previous line width of the above help
> > because on standard 80-width window the help now gets truncated in
> > make menuconfig.
> >
> > Refer this screenshot: https://i.imgur.com/9LgttpC.png
> >
> > Sorry for the confusion, I was already expecting this comment. The
> > patch had a few words added, hence it feels like many lines have
> > changed. However, no line actually exceeds 80 width.
> >
> > Longest line is still 80-width max. Do you prefer I reduce it to a
> > lower number like 70?
>
>         I'm checking in menuconfig where the help text is displayed.
> The word "lasting" is visible up to "last". So, 3 columns are not
> visible. In editor, this line is 84, may be up to 80 should be good.
> You are using editor that represents Tabs as 4 spaces, that is why
> it looks like it fits in 80. Open Kconfig in less. But in editor/less
> does not matter because menuconfig simply ignores the leading spaces
> in Kconfig and considers the text length which should be no more
> than 70.
>
> Regards
>
> --
> Julian Anastasov <ja@ssi.bg>
>


-- 
Cheers,
Abhijeet (https://abhi.host)