Date: Thu, 6 Mar 2014 12:23:22 +0100 From: Peter Holm <peter@holm.cc> To: Alan Somers <asomers@freebsd.org> Cc: "freebsd-testing@freebsd.org" <freebsd-testing@freebsd.org> Subject: Re: Test scenario for sysctl kern.maxfiles Message-ID: <20140306112322.GA10664@x2.osted.lan> In-Reply-To: <CAOtMX2hUJ2Hc62bG1jitbQbiHtb8b8Jm8iWaP4VaJPuADXR=Kw@mail.gmail.com> References: <20140305085806.GA70478@x2.osted.lan> <CAOtMX2hUJ2Hc62bG1jitbQbiHtb8b8Jm8iWaP4VaJPuADXR=Kw@mail.gmail.com>
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On Wed, Mar 05, 2014 at 10:08:49AM -0700, Alan Somers wrote: > On Wed, Mar 5, 2014 at 1:58 AM, Peter Holm <peter@holm.cc> wrote: > > Here's an attempt to verify that increasing kern.maxfiles works as > > expected. > > > > http://people.freebsd.org/~pho/kern_descrip_test-v3.diff > > -- > > Peter > > 1) done should be of type "static volatile sig_atomic_t", not int, > because it's set by signal handlers. > Yes, that is nicer (I learned something new today :-). But the use here works because there is a call to usleep(3) after each test, forcing the compiler to reload the "done" variable. > 2) using atexit() to register a cleanup routing is a hack. No doubt Why do you say that using atexit(3) is a hack? > you already noticed that it's difficult to use Kyua's builtin cleanup > capabilities because of the need to pass the value of oldmaxfiles. I > too have experienced that frustration. Is there any way to pass > values from the body of a testcase to its cleanup? Using > atf_tc_set_md_var() would be one way, but the man page suggests that > that function cannot be called from the body. Julio, is there a > better way to do this? > > 3) Why do you openfiles(oldmaxfiles + 50, 0) instead of just > openfiles(oldmaxfiles) ? It seems that the latter would also verify > the assertion. > The idea is to test "expansion" -> expand maxfiles to maxfiles + 1000 and test "more than was possible before". But that of cause only works on a moderately loaded host. > 4) openfiles(oldmaxfiles + 50, 0) will fail if there are already 950 > open files. A quick check on freefall showed that kern.openfiles was > 935. Perhaps you should try opening openfiles(oldmaxfiles - > kern.openfiles + 50, 0). That wouldn't be perfect, due to races, but > it would be better. > Yes I agree, that would be better. Now this raises an interesting question for me: Which environment do you guys expect ATF to run in? If it is hosts like freefall, any resource hogging tests are out of the question I would think. -- Peter
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