> -----Original Message----- > From: Wei Liu [mailto:[email protected]] > Sent: 20 March 2014 10:49 > To: Zoltan Kiss > Cc: Ian Campbell; Wei Liu; [email protected]; > [email protected]; [email protected]; Jonathan Davies; > Paul Durrant > Subject: Re: [PATCH net-next v7 9/9] xen-netback: Aggregate TX unmap > operations > > On Wed, Mar 19, 2014 at 09:16:05PM +0000, Zoltan Kiss wrote: > > Hi, > > > > I'm thinking about revoking this patch: it's value is pretty small, > > but it causes performance regression on Win7 guests. And probably it > > is not the best solution for this problem. It might be the delay it > > takes the dealloc thread to be scheduled is enough. > > What do you think? > > > > Can you elaborate? What makes Win7 so special? What's performance > impact to other guests? >
It won't be Win7 specifically I expect. It will likely by any version of Windows, or any other OS that limits the TXs-in-flight so aggressively. Basically you need to TX-complete reasonably frequently otherwise your throughput drops off a lot. IIRC at Solarflare we found every ~500us to be just about frequent enough for hitting 10G. Paul -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
