Re: [Samba] Re: samba on quad core vs dual core
Samba will use all the cores you can give it - so long as you have at least more clients than cores. Jeremy. While I have found that to be true in my environment, I have also found that MOST smbd's end up on Core 0 MOST of the time. This is true even if I am hammering a 10 Gigabit network adapter (i.e., sending out 700 MB/sec via Samba distributed to 30 users), with total CPU utilization only about 70 percent of one core. Maybe this is optimal behavior. I tried to start a thread on this list a while back about understanding what WOULD be optimal, and nobody had much to say. I think it would be an interesting discussion. NFS seems to make use of multicores in a more even way. That doesn't mean the NFS behavior is better. Andy -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/listinfo/samba
Re: [Samba] Re: samba on quad core vs dual core
On Tue, Dec 09, 2008 at 03:17:53PM -0500, Andy Liebman wrote: Samba will use all the cores you can give it - so long as you have at least more clients than cores. Jeremy. While I have found that to be true in my environment, I have also found that MOST smbd's end up on Core 0 MOST of the time. This is true even if I am hammering a 10 Gigabit network adapter (i.e., sending out 700 MB/sec via Samba distributed to 30 users), with total CPU utilization only about 70 percent of one core. Maybe this is optimal behavior. I tried to start a thread on this list a while back about understanding what WOULD be optimal, and nobody had much to say. I think it would be an interesting discussion. NFS seems to make use of multicores in a more even way. That doesn't mean the NFS behavior is better. smbd is a userspace process, so we don't do anything clever w.r.t. distributing ourselves across cores, only let the OS do it's stuff. I'm guessing in your case you're seeing the effects of the OS accumulating the network interrupt traffic on the one processor that's handling that card. Jeremy. -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/listinfo/samba
Re: [Samba] Re: samba on quad core vs dual core
On Tue, Dec 09, 2008 at 03:17:53PM -0500, Andy Liebman wrote: Samba will use all the cores you can give it - so long as you have at least more clients than cores. Jeremy. While I have found that to be true in my environment, I have also found that MOST smbd's end up on Core 0 MOST of the time. This is true even if I am hammering a 10 Gigabit network adapter (i.e., sending out 700 MB/sec via Samba distributed to 30 users), with total CPU utilization only about 70 percent of one core. Have you measured how much you can pump out over that adapter using raw tcp using, say, iperf or so? My guess would be that 700MBytes/second are not way off what it can do. Maybe this is optimal behavior. I tried to start a thread on this list a while back about understanding what WOULD be optimal, and nobody had much to say. If you really only use 70% of one core, then my feeling would be that this is indeed what you should expect for cache locality. But to say for sure a *lot* deeper investigations are necessary. Volker pgpN5HSmsd737.pgp Description: PGP signature -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/listinfo/samba
Re: [Samba] Re: samba on quad core vs dual core
On Mon, Dec 08, 2008 at 02:28:19PM -0800, Mark Nienberg wrote: I guess what I'm wondering is will samba actually use all those cores or will it just use one, in which case maybe I'd be better of with a faster dual core than a quad. You're right though, that the server I am replacing is an older single core chip and it doesn't have any trouble keeping up with demand, so probably any recent chip will work fine. Samba will use all the cores you can give it - so long as you have at least more clients than cores. Jeremy. -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/listinfo/samba
Re: [Samba] Re: samba on quad core vs dual core
I guess what I'm wondering is will samba actually use all those cores or will it just use one, in which case maybe I'd be better of with a faster dual core than a quad. You're right though, that the server I am replacing is an older single core chip and it doesn't have any trouble keeping up with demand, so probably any recent chip will work fine. Each user gets its own samba process (and threads) so if there are more then 2 logged in users samba will definitely make use of the extra cores. John -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/listinfo/samba
