LinuxLists.cc - [PATCH v2] net/sctp/ulpevent.c: Deinline sctp_ulpevent_set

2017-06-21 17:03:33

Subject: [PATCH v2] net/sctp/ulpevent.c: Deinline sctp_ulpevent_set_owner, save 1616 bytes

This function compiles to 147 bytes of machine code. 13 callsites.

I'm no expert on SCTP events, but quick reading of SCTP docs tells me that
SCTP events are not happening on every packet.
They are ASSOC_CHANGE, PEER_ADDR_CHANGE, REMOTE_ERROR and such.
Does not look performance critical.

Signed-off-by: Denys Vlasenko <[email protected]>
CC: Vlad Yasevich <[email protected]>
CC: Neil Horman <[email protected]>
CC: David Miller <[email protected]>
CC: [email protected]
CC: [email protected]
CC: [email protected]
---
Changed since v1:
* reindented function argument list

net/sctp/ulpevent.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sctp/ulpevent.c b/net/sctp/ulpevent.c
index ec2b3e0..bc3f495 100644
--- a/net/sctp/ulpevent.c
+++ b/net/sctp/ulpevent.c
@@ -88,8 +88,8 @@ int sctp_ulpevent_is_notification(const struct sctp_ulpevent *event)
/* Hold the association in case the msg_name needs read out of
* the association.
*/
-static inline void sctp_ulpevent_set_owner(struct sctp_ulpevent *event,
- const struct sctp_association *asoc)
+static void sctp_ulpevent_set_owner(struct sctp_ulpevent *event,
+ const struct sctp_association *asoc)
{
struct sctp_chunk *chunk = event->chunk;
struct sk_buff *skb;
--
1.8.3.1

2017-06-21 19:24:51

by Marcelo Ricardo Leitner

[permalink] [raw]

Subject: Re: [PATCH v2] net/sctp/ulpevent.c: Deinline sctp_ulpevent_set_owner, save 1616 bytes

On Wed, Jun 21, 2017 at 07:03:27PM +0200, Denys Vlasenko wrote:
> This function compiles to 147 bytes of machine code. 13 callsites.
>
> I'm no expert on SCTP events, but quick reading of SCTP docs tells me that
> SCTP events are not happening on every packet.
> They are ASSOC_CHANGE, PEER_ADDR_CHANGE, REMOTE_ERROR and such.
> Does not look performance critical.
>
> Signed-off-by: Denys Vlasenko <[email protected]>
> CC: Vlad Yasevich <[email protected]>
> CC: Neil Horman <[email protected]>
> CC: David Miller <[email protected]>
> CC: [email protected]
> CC: [email protected]
> CC: [email protected]

Acked-by: Marcelo Ricardo Leitner <[email protected]>

Just wondering, are you conducting further research on this topic?
Because we probably could use such review on SCTP stack.

> ---
> Changed since v1:
> * reindented function argument list
>
> net/sctp/ulpevent.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/sctp/ulpevent.c b/net/sctp/ulpevent.c
> index ec2b3e0..bc3f495 100644
> --- a/net/sctp/ulpevent.c
> +++ b/net/sctp/ulpevent.c
> @@ -88,8 +88,8 @@ int sctp_ulpevent_is_notification(const struct sctp_ulpevent *event)
> /* Hold the association in case the msg_name needs read out of
> * the association.
> */
> -static inline void sctp_ulpevent_set_owner(struct sctp_ulpevent *event,
> - const struct sctp_association *asoc)
> +static void sctp_ulpevent_set_owner(struct sctp_ulpevent *event,
> + const struct sctp_association *asoc)
> {
> struct sctp_chunk *chunk = event->chunk;
> struct sk_buff *skb;
> --
> 1.8.3.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-sctp" in
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> More majordomo info at http://vger.kernel.org/majordomo-info.html
>

2017-06-21 19:45:08

by Denys Vlasenko

[permalink] [raw]

Subject: Re: [PATCH v2] net/sctp/ulpevent.c: Deinline sctp_ulpevent_set_owner, save 1616 bytes

On 06/21/2017 09:24 PM, Marcelo Ricardo Leitner wrote:
> On Wed, Jun 21, 2017 at 07:03:27PM +0200, Denys Vlasenko wrote:
>> This function compiles to 147 bytes of machine code. 13 callsites.
>>
>> I'm no expert on SCTP events, but quick reading of SCTP docs tells me that
>> SCTP events are not happening on every packet.
>> They are ASSOC_CHANGE, PEER_ADDR_CHANGE, REMOTE_ERROR and such.
>> Does not look performance critical.
>>
>> Signed-off-by: Denys Vlasenko <[email protected]>
>> CC: Vlad Yasevich <[email protected]>
>> CC: Neil Horman <[email protected]>
>> CC: David Miller <[email protected]>
>> CC: [email protected]
>> CC: [email protected]
>> CC: [email protected]
>
> Acked-by: Marcelo Ricardo Leitner <[email protected]>
>
> Just wondering, are you conducting further research on this topic?
> Because we probably could use such review on SCTP stack.

Here is the list of sctp inlines which has any (however small)
benefit when deinlined.

filename:lineno:inline_name:lines_of_source_code:saved_bytes_by_deinlining:size_of_code_of_deinlined_function

include/net/sctp/command.h:228:sctp_add_cmd_sf:7:8306:38
net/sctp/ulpevent.c:91:sctp_ulpevent_set_owner:13:1616:147
include/net/sctp/sctp.h:414:sctp_skb_set_owner_r:10:934:75
net/sctp/input.c:840:sctp_hash_key:13:896:359
net/sctp/input.c:823:sctp_hash_obj:13:704:409
include/net/sctp/checksum.h:60:sctp_compute_cksum:13:595:85
net/sctp/input.c:800:sctp_hash_cmp:18:320:124
net/sctp/socket.c:117:sctp_wspace:19:256:76
include/net/sctp/sctp.h:272:sctp_max_rto:7:204:68
net/sctp/socket.c:173:sctp_verify_addr:15:192:72
include/net/sctp/checksum.h:46:sctp_csum_update:4:147:21
include/net/sctp/sctp.h:519:param_type2af:8:134:35
include/net/sctp/sctp.h:399:sctp_list_dequeue:7:123:59
include/net/sctp/sctp.h:596:sctp_transport_dst_check:4:120:60
include/net/sctp/sctp.h:435:sctp_frag_point:12:65:65
net/sctp/outqueue.c:82:sctp_outq_dequeue_data:10:64:87
include/net/sctp/command.h:243:sctp_next_cmd:4:64:37
include/net/sctp/sm.h:347:sctp_data_size:6:19:19

For .c files, the patches are trivial and I have them auto-generated,
I'll send them to you privately to save you the mechanical work.

Unfortunately, for inlines in .h files this does not work
(a human is needed to decide where to more the function).

Of course, not every deinlining makes sense.

2017-06-23 20:39:28

by Marcelo Ricardo Leitner

[permalink] [raw]