Date: Tue, 10 Aug 2010 00:16:24 -0400 From: Joshua Boyd <boydjd@jbip.net> To: Jeremy Chadwick <freebsd@jdc.parodius.com> Cc: freebsd-stable@freebsd.org, Ivan Voras <ivoras@freebsd.org> Subject: Re: 8-STABLE Slow Write Speeds on ESXI 4.0 Message-ID: <AANLkTikfo%2BaXCG5ix2nO15Dx-YSv3w0MMEt_rz=O6z%2Bp@mail.gmail.com> In-Reply-To: <20100810040519.GA21921@icarus.home.lan> References: <AANLkTi=FNZ%2B=4yMPJBu%2BucGJiHqwMwQvoGcgqB%2BtPJF2@mail.gmail.com> <i3jhn0$ovp$1@dough.gmane.org> <AANLkTik%2BS2fe-sS242OXQprsEA4Oh4t6-CvBCuBCASz7@mail.gmail.com> <AANLkTimMA6OQKt-d6ecM=GmG2ciBTis-nHNovEwvjCB-@mail.gmail.com> <AANLkTimu2JoC6bmaBcSY3e5ovBPnwZ_s_zbRK=v8h7f6@mail.gmail.com> <AANLkTimuPnac_h-ipCyD76j%2B0HGttBxDYyTNdtdU0_sm@mail.gmail.com> <20100809161124.GA4618@icarus.home.lan> <AANLkTimYKupOZXDgL6O2SRxp3JHJcMGSrcVK697tKPss@mail.gmail.com> <20100810040519.GA21921@icarus.home.lan>
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On Tue, Aug 10, 2010 at 12:05 AM, Jeremy Chadwick <freebsd@jdc.parodius.com>wrote: > On Mon, Aug 09, 2010 at 11:59:46PM -0400, Joshua Boyd wrote: > > On Mon, Aug 9, 2010 at 12:11 PM, Jeremy Chadwick > > <freebsd@jdc.parodius.com>wrote: > > > > > On Mon, Aug 09, 2010 at 05:12:21PM +0200, Ivan Voras wrote: > > > > On 9 August 2010 16:55, Joshua Boyd <boydjd@jbip.net> wrote: > > > > > On Sat, Aug 7, 2010 at 1:58 PM, Ivan Voras <ivoras@freebsd.org> > wrote: > > > > >> > > > > >> On 7 August 2010 19:03, Joshua Boyd <boydjd@jbip.net> wrote: > > > > >> > On Sat, Aug 7, 2010 at 7:57 AM, Ivan Voras <ivoras@freebsd.org> > > > wrote: > > > > >> > > > > >> >> It's unlikely they will help, but try: > > > > >> >> > > > > >> >> vfs.read_max=32 > > > > >> >> > > > > >> >> for read speeds (but test using the UFS file system, not as a > raw > > > > >> >> device > > > > >> >> like above), and: > > > > >> >> > > > > >> >> vfs.hirunningspace=8388608 > > > > >> >> vfs.lorunningspace=4194304 > > > > >> >> > > > > >> >> for writes. Again, it's unlikely but I'm interested in results > you > > > > >> >> achieve. > > > > >> >> > > > > >> > > > > > >> > This is interesting. Write speeds went up to 40MBish. Still > slow, > > > but 4x > > > > >> > faster than before. > > > > >> > [root@git ~]# dd if=/dev/zero of=/var/testfile bs=1M count=250 > > > > >> > 250+0 records in > > > > >> > 250+0 records out > > > > >> > 262144000 bytes transferred in 6.185955 secs (42377288 > bytes/sec) > > > > >> > [root@git ~]# dd if=/var/testfile of=/dev/null > > > > >> > 512000+0 records in > > > > >> > 512000+0 records out > > > > >> > 262144000 bytes transferred in 0.811397 secs (323077424 > bytes/sec) > > > > >> > So read speeds are up to what they should be, but write speeds > are > > > still > > > > >> > significantly below what they should be. > > > > >> > > > > >> Well, you *could* double the size of "runningspace" tunables and > try > > > that > > > > >> :) > > > > >> > > > > >> Basically, in tuning these two settings we are cheating: > increasing > > > > >> read-ahead (read_max) and write in-flight buffering (runningspace) > in > > > > >> order to offload as much IO to the controller (in this case > vmware) as > > > > >> soon as possible, so to reschedule horrible IO-caused context > switches > > > > >> vmware has. It will help sequential performance, but nothing can > help > > > > >> random IOs. > > > > > > > > > > Hmm. So what you're saying is that FreeBSD doesn't properly support > the > > > ESXI > > > > > controller? > > > > > > > > Nope, I'm saying you will never get raw disk-like performance with > any > > > > "full" virtualization product, regardless of specifics. If you want > > > > performance, go OS-level (like jails) or some example of > > > > paravirtualization. > > > > > > > > > I'm going to try 7.3-RELEASE today, just to make sure that this > isn't a > > > > > regression of some kind. It seems from reading other posts that > this > > > used to > > > > > work properly and satisfactorily. > > > > > > > > Nope, I've been messing around with VMWare for a long time and the > > > > performance penalty was always there. > > > > > > I thought Intel VT-d was supposed to help address things like this? > > > > > > > Our ESXI boxes are AMD rigs, so VT-d doesn't help here. > > AMD offers the same technology; it's called AMD-Vi these days, and was > previously known as IOMMU. I don't have any familiarity with it. > As far as I know, all it gets you is passthrough. > > -- > | Jeremy Chadwick jdc@parodius.com | > | Parodius Networking http://www.parodius.com/ | > | UNIX Systems Administrator Mountain View, CA, USA | > | Making life hard for others since 1977. PGP: 4BD6C0CB | > > -- Joshua Boyd JBipNet E-mail: boydjd@jbip.net http://www.jbip.net
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