From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <499D68A5.8020002@domain.hid> Date: Thu, 19 Feb 2009 15:11:49 +0100 From: Jan Kiszka MIME-Version: 1.0 References: <499D359C.3060805@domain.hid> <499D3801.5040303@domain.hid> <499D3FE6.4030208@domain.hid> <499D5B0A.7020608@domain.hid> <499D5FC4.4030303@domain.hid> <499D67A6.7000301@domain.hid> In-Reply-To: <499D67A6.7000301@domain.hid> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-core] XENO_OPT_SYS_STACKPOOLSZ vs. switchtest List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: rpm@xenomai.org Cc: xenomai-core Philippe Gerum wrote: > Jan Kiszka wrote: >> Gilles Chanteperdrix wrote: >>> Jan Kiszka wrote: >>>> Gilles Chanteperdrix wrote: >>>>> Jan Kiszka wrote: >>>>>> Hi Gilles, >>>>>> >>>>>> how much XENO_OPT_SYS_STACKPOOLSZ do I need to run switchtest for >>>>>> default settings? At least on x86-64, the default 32K is not enough. >>>>>> Unless we talk about GB ;), maybe it makes sense to adjust the default >>>>>> size accordingly. >>>>> It depends on the arguments you pass to switchtest. >>>> None, ie. the default settings. >>> Then 6 kernel-space tasks are created. Since switchtest is not the >> 6*4 is 20k... Ah, the well-known allocator overhead, I guess. Will try >> with >= 40k. >> > > Actually, it is not really an overhead, but rather the fact that it wants at > least two initially free pages per heap. That would make 22K. The problem is that the management overhead is rounded up to another full page, requiring a 8K allocation per 4K request. Reminds me of TLSF - if I only had the time... :) Jan -- Siemens AG, Corporate Technology, CT SE 2 Corporate Competence Center Embedded Linux