Date: Mon, 26 Oct 2009 14:10:22 +0100 From: Arnaud Houdelette <arnaud.houdelette@tzim.net> To: Jaime Bozza <jbozza@mindsites.com> Cc: "freebsd-stable@freebsd.org" <freebsd-stable@freebsd.org>, Jacob Myers <jacob@whotookspaz.org> Subject: Re: Possible scheduler (SCHED_ULE) bug? Message-ID: <4AE59FBE.6060904@tzim.net> In-Reply-To: <CF092998EA82AE4D83AF9C9ECA9A8BDE02EB411A8F@ATLAS.msg.local> References: <CF092998EA82AE4D83AF9C9ECA9A8BDE02EB411A85@ATLAS.msg.local> <d5992baf0910231149qa4e89fdx2e1cde9b2a529cd3@mail.gmail.com> <CF092998EA82AE4D83AF9C9ECA9A8BDE02EB411A8E@ATLAS.msg.local> <4AE2232E.10406@whotookspaz.org> <CF092998EA82AE4D83AF9C9ECA9A8BDE02EB411A8F@ATLAS.msg.local>
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Jaime Bozza a écrit : >>> The additional information I have (over the PR) is that: >>> 1) Files over 64K cause the problem, not just larger files >>> >> I thought it was over 1 MB or so. But maybe I'm wrong. ISTR that I >> couldn't trigger it with some images of around 70K. >> > > I discovered it originally with a 72K file. After some tests, I found a 63K file worked and a 65K file didn't. When I get back into the office, I can test the actual boundary (65535, 65536, 65537, etc), but 64K seems pretty logical. > > >>> 2) switching over to SCHED_4BSD eliminates the problem - system no >>> >> longer locks. >> I will have to test this. This is indeed interesting... >> >> >>> 3) 7.2 amd64 doesn't have the problem - Tested a similar >>> >> configuration and was not able to duplicate on amd64 at all. >> I can replicate this problem on FreeBSD 7.2/amd64 reliably. >> > > I haven't tried larger files - Maybe the boundary is different on amd64? Doing some quick tests right now, I was able to upload a 100MB file without a problem, but this is an AMD64 system with SMP, plus the filesystem is all ZFS, so there are too many things different. I'll have to setup a system that closely mirrors the rest of my tests (UFS, ULE, no SMP, etc) before I can say I'm not having a problem there. > > Jaime > I had the same issue using 7.1 amd64, with ZFS, no SMP. Not really sure what is the size boundary. I can't really test either, as the machine is remote. But I confirm that each tentative upload of certain relatively 'big' files (around 1MB) with wordpress hanged the system before I switched from sendfile to writev. I might do some test on amd64 7.2 with no SMP if it can be of any use ? Arnaud
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