Hello there, since I installed CentOS6 few months ago (kept up-to-date using yum), I'm facing very poor performances when writing to USB pendrives. The hardware: a Dell Latitude E6500 laptop (Intel Core Duo P8600 @2.40Ghz), 4Go RAM + 4Go swap, several USB2 pendrives of various brands (less than old, all formatted as vfat). When I perform a copy (with cp or midnight commander, copying big AVI files between 300Mo to 1.4Go) to those devices, whatever the source is on the same device or on another disk, I notice that the CPU activity shows 2 phases as far as I can see with the Gnome system monitor applet: - a phase where both CPUs show less than 20% of activity, and IOWait is <80%. It lasts the time I would expect such copy to last (say, it's like writing at 1-4MB/sec to such devices, which is reasonable or expected). - a phase, at least twice as long as 1st phase but this ratio depends on the file copy size, where CPUs show <5% of activity but IOWait is at 100%. During phase 1, system and applications are responsive, as expected during a file copy to external USB2 disks. During phase 2, system is slow, applications are often non responsive. I was not facing this behaviour w/ Fedora 11, not w/ the Windows XP system also installed on this laptop. I'm not facing such poor performances when writing to externals SATA drives (thru the same USB2 ports), even formatted as vfat. Neither when writing to those pendrives from another hardware system. `hdparm -tT` is useless here. I wonder if some mount options aren't wrong with USB pendrives, see: /dev/sdd1 on /media/monolith type vfat (rw,nosuid,nodev,uhelper=udisks,shortname=mixed,dmask=0077,utf8=1,flush) my suspicion is about the flush option, which I find atypical here. BTW, I'm still unable to control the mount options that are automatically set by Gnome - even if I can mount manually if I want. Any hint? Regards, -- wwp -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 198 bytes Desc: not available URL: <http://lists.centos.org/pipermail/centos/attachments/20120110/8b163d9e/attachment-0005.sig>
From: wwp <subscript at free.fr>> I wonder if some mount options aren't wrong with USB pendrives, see: > ? /dev/sdd1 on /media/monolith type vfat > (rw,nosuid,nodev,uhelper=udisks,shortname=mixed,dmask=0077,utf8=1,flush) > my suspicion is about the flush option, which I find atypical here.I guess it is to be safe in case users remove their usb keys without unmounting first... JD
Blah, blah, blah, Being blocked again, still appears to be based on new content vs. included content. Which makes it very annoying when I want to include context for my response. blah, blah, blah, new content................. Hi, wwp, wwp wrote:> On Wed, 11 Jan 2012 16:31:43 +0100 Ljubomir Ljubojevic <office at plnet.rs>wrote:>> On 01/11/2012 08:45 AM, wwp wrote: >> > On Tue, 10 Jan 2012 08:57:14 -0800 (PST) John Doe<jdmls at yahoo.com> >> wrote: >> >> From: wwp<subscript at free.fr> >> >> >> >>> I wonder if some mount options aren't wrong with USB pendrives, see: >> >>> /dev/sdd1 on /media/monolith type vfat >> >>> (rw,nosuid,nodev,uhelper=udisks,shortname=mixed,dmask=0077,utf8=1,flush)my suspicion is about the flush option, which I find atypical here. <snip>> ehci_hcd does manage my devices (it's not a loadable module, apparentlycompiled in kernel instead), see for instance:> > kernel: usb 2-2: new high speed USB device using ehci_hcd and address 28<snip> This may be a dumb question, but have you done an lsusb? I'd be curious - I know that on my brand new, as of a few months ago, Dell I have two kinds of USB ports, 1.1 and 2.0. We also have some 1.1 webcams... and some 1.0. See if your pen drive's in a slower port. mark
On Tuesday 10 January 2012 16:17:54 wwp wrote:> Hello there, > > > since I installed CentOS6 few months ago (kept up-to-date using yum), > I'm facing very poor performances when writing to USB pendrives. > > The hardware: a Dell Latitude E6500 laptop (Intel Core Duo P8600 > @2.40Ghz), 4Go RAM + 4Go swap, several USB2 pendrives of various brands > (less than old, all formatted as vfat). > > > When I perform a copy (with cp or midnight commander, copying big AVI > files between 300Mo to 1.4Go) to those devices, whatever the source is > on the same device or on another disk, I notice that the CPU activity > shows 2 phases as far as I can see with the Gnome system monitor applet: > > - a phase where both CPUs show less than 20% of activity, and IOWait > is <80%. It lasts the time I would expect such copy to last (say, > it's like writing at 1-4MB/sec to such devices, which is reasonable > or expected). > > - a phase, at least twice as long as 1st phase but this ratio depends > on the file copy size, where CPUs show <5% of activity but IOWait is > at 100%. > > During phase 1, system and applications are responsive, as expected > during a file copy to external USB2 disks. During phase 2, system is > slow, applications are often non responsive. > > I was not facing this behaviour w/ Fedora 11, not w/ the Windows XP > system also installed on this laptop. > > I'm not facing such poor performances when writing to externals SATA > drives (thru the same USB2 ports), even formatted as vfat. Neither when > writing to those pendrives from another hardware system. > > `hdparm -tT` is useless here. > > I wonder if some mount options aren't wrong with USB pendrives, see: > /dev/sdd1 on /media/monolith type vfat (rw,nosuid,nodev,uhelper=udisks,shortname=mixed,dmask=0077,utf8=1,flush) > my suspicion is about the flush option, which I find atypical here. > > BTW, I'm still unable to control the mount options that are > automatically set by Gnome - even if I can mount manually if I want. > > Any hint? > > > Regards, > >There's been a loooong discussion in various threads in Archlinux. For example: https://bbs.archlinux.org/viewtopic.php?id=112846 A solution could be "echo madvise > /sys/kernel/mm/transparent_hugepage/defrag" from: https://bbs.archlinux.org/viewtopic.php?pid=1033648#p1033648 Because trying: "echo never > /sys/kernel/mm/transparent_hugepage/defrag" Might break hibernation/suspending Notice: havent tested this things in CentOS ;) Regards