Date: Mon, 6 Mar 2017 12:40:48 +0100 From: Hans Petter Selasky <hps@selasky.org> To: Markus Rechberger <mrechberger@gmail.com> Cc: freebsd-multimedia@freebsd.org Subject: Re: What is wrong with FreeBSD and USB Support Message-ID: <ecf90533-7777-df2a-5fa2-89d5b1f0c7d7@selasky.org> In-Reply-To: <CA%2BO4pC%2ByGM3CwNgAsKAp3CQtdCFCPZ8fukG2aKK4oO3MU=VPfA@mail.gmail.com> 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>
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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. --HPS
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