smbd: High CPU usage

Stefan Metzmacher metze at
Thu Jul 19 05:40:27 UTC 2018

Am 19.07.2018 um 07:32 schrieb Volker Lendecke via samba-technical:
> On Wed, Jul 18, 2018 at 04:16:46PM -0700, Jeremy Allison via samba-technical wrote:
>> On Wed, Jul 18, 2018 at 09:20:10PM +0300, Vadim Lazovskiy via samba-technical wrote:
>>> I would not agree.
>>> sendfile is great. It makes you able to serve content directly from disk to
>>> network without unnessesery copying to userspace. It saves you lots
>>> syscalls and context switching.
>>> As for our workload profile (1-2Gbit per server) it really saves CPU time.
>>> If someone of samba developers treat this as bug and eager to fix it I
>>> could provide extra information and do some debugging.
>> Here is a full patchset that should handle all platforms
>> for which we support sendfile(). Can you try it out and confirm it
>> fixes your issue ?
> I know syscalls are cheap, but don't the additional fcntl ones kill
> the performance advantage somewhat? We had discussions with a
> MIPS-based vendor in the past. On that platform (don't remember the
> exact OS version), syscalls were pretty expensive.

What about changing to blocking mode only when we actually got EAGAIN?


-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: OpenPGP digital signature
URL: <>

More information about the samba-technical mailing list