Date: Tue, 13 Oct 2009 13:30:02 -0500 (CDT) From: Larry Rosenman <ler@lerctr.org> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-stable@freebsd.org Subject: Re: Extreme console latency during disk IO (8.0-RC1, previous releases also affected according to others) Message-ID: <alpine.BSF.2.00.0910131328400.34883@thebighonker.lerctr.org> In-Reply-To: <9bbcef730910131057i71db846et1f0d4aeadef5e302@mail.gmail.com> References: <E316139E-FFCF-432F-8DCE-62B120C38E55@exscape.org> <CC16B639-7A75-4016-A8A8-5C59E9CD5E95@exscape.org> <hb1qs0$qjd$1@ger.gmane.org> <alpine.BSF.2.00.0910131406340.26071@fledge.watson.org> <9bbcef730910130633w150571a0k461fb4e67a51fb1d@mail.gmail.com> <B5BA3ACC-BC06-4042-8434-0D9395A0F478@freebsd.org> <hb23i7$opq$1@ger.gmane.org> <alpine.BSF.2.00.0910130957540.26159@thebighonker.lerctr.org> <9bbcef730910131057i71db846et1f0d4aeadef5e302@mail.gmail.com>
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On Tue, 13 Oct 2009, Ivan Voras wrote: > 2009/10/13 Larry Rosenman <ler@lerctr.org>: > >>>>> note huge packet loss. It looks like it's VM fault or something like it. >>>> >>>> It sounds like the VM is failing to execute the guest during certain >>>> types of I/O. A bit of scheduler tracing in the host OS probably wouldn't go >>>> amiss to confirm that the VM really is suspending the guest >>> >>> It's VMWare ESXi underneath, which is *Officially Not Linux* though some >>> ducks may disagree - anyway, I suspect tracing the host in this way is next >>> to impossible without some kind of diamondium-level contract. >>> >> What information do you need? I have a platinum VMWare contract. >> >> What version of ESXi? > > Hi, > > It is ESXi 3.5 - but if the problem is really in ESXi I presume anyone > could reproduce it. My setup is nothing special - Xeon 5405, 8 GB RAM, > SATA drives on ICH9. > > As for what data is needed, it depends on what you can get - from this > discussion thread it looks like it would be enough to verify that disk > IO doesn't leave VM processes waiting (i.e. that disk IO doesn't > interfere with CPU-bound or idle virtual machines). Though now when I > think of it - doesn't Linux ATA driver poll IO in some funky way, > expecting to get lower latency that way? > Have you looked at the information available via the performance tab(s) in the client pointing at the ESXi server? -- Larry Rosenman http://www.lerctr.org/~ler Phone: +1 512-248-2683 E-Mail: ler@lerctr.org US Mail: 430 Valona Loop, Round Rock, TX 78681-3893
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