Date: Mon, 6 Mar 2017 12:42:50 +0100 From: Markus Rechberger <mrechberger@gmail.com> To: Hans Petter Selasky <hps@selasky.org> Cc: freebsd-multimedia@freebsd.org Subject: Re: What is wrong with FreeBSD and USB Support Message-ID: <CA%2BO4pC%2BgOhZ=CNeY5dFJXhS7cLpbE1-SCtwUc9C%2BLV-mX6v3Cg@mail.gmail.com> In-Reply-To: <ecf90533-7777-df2a-5fa2-89d5b1f0c7d7@selasky.org> References: <CA%2BO4pCK4%2B1rE5ft4Boy_3xPdCxK31UtTQ2BYpnBUn5jxZr%2Bz_g@mail.gmail.com> <CA%2BO4pCJr5Bq-sgjzvZQB-mFRT6x7Tp3psga6f__V9Ag-=v-mhw@mail.gmail.com> <CA%2BO4pC%2Bf5xzOjENKSJu_sQeaiN3XL3WiTcRQvm4vVweQ71Xtrg@mail.gmail.com> <CA%2BO4pC%2B1t67ODF7bkyVhcojXTLnFkS28RbFAc%2Be-tjNncogMAQ@mail.gmail.com> <CA%2BO4pCLRJRFG8Sv6C=FK6myBDPdUfhNjZ88P=e1uuH2=ojB75w@mail.gmail.com> <1aff0983-deb6-2884-472c-bb1e1037275c@selasky.org> <CA%2BO4pCLLSgdFOpJvnrD_F5Zh1aOGQexjiKKSiPbpcsKWs8wgUQ@mail.gmail.com> <CA%2BO4pCLvWi3hpLKfXiabQ6en0=PryXQC91tqeuj3VPCE8HQ_jg@mail.gmail.com> <9fe561d0-3d8b-8725-98d4-37c2eb094ae9@selasky.org> <CA%2BO4pC%2ByGM3CwNgAsKAp3CQtdCFCPZ8fukG2aKK4oO3MU=VPfA@mail.gmail.com> <ecf90533-7777-df2a-5fa2-89d5b1f0c7d7@selasky.org>
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On Mon, Mar 6, 2017 at 12:40 PM, Hans Petter Selasky <hps@selasky.org> wrote: > Hi, > > On 03/06/17 12:36, Markus Rechberger wrote: >> >> libusb20 - usb userspace interface - usb - roundtrip problem that >> causes this high latency. > > > If you are using an old FreeBSD kernel, more than two years old, there was > an issue where malloc() was used in the generic IOCTL path. This piece has > in later versions of FreeBSD been replace with a conditional on-stack > buffer. If you have this issue you should see high CPU usage on one of the > CPU cores while doing USB transfers fast. > I'm using FreeBSD 11 the latest one.
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