[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]] [[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable id="license" text="Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled [[GNU Free Documentation License|/fdl]]."]]"""]] [[!tag open_issue_hurd]] IRC, freenode, #hurd, 2011-07-25 < youpi> Mmm, typing something on the mach console triggers a write on the disk < youpi> because the /dev/console node gets updated < youpi> I don't really see why < youpi> (yes, just typing at the bash prompt, not even running something) < youpi> typing during the sleep command (i.e. mere tty echo) doesn't trigger it, however < youpi> running bash's echo does trigger it < braunr> during sleep, the glibc stream functions handle I/O, while with bash, its readline takes care of it, right ? < youpi> /bin/echo too < youpi> during sleep it's the tty process which handles I/O < braunr> the write may be due to a write time update on the inode < braunr> modification* time < youpi> probably yes, but how so? < youpi> ext2fs is only supposed to pass the thing to the console translator < braunr> not sure < youpi> actually, ext2fs even isn't supposed to come into play when it's about typing at the bash prompt < youpi> once it's opened, isn't the port for /dev/console supposed to be directly to the translator there? < braunr> i think so < youpi> (s/tty/term/ in what I said) < braunr> well, it's certain < youpi> so I don't see how ext2fs can be triggered to write an atime or mtime < braunr> what does rpctrace say ? < youpi> io_read_request and io_write_request < youpi> braunr: it doesn't happen at the login prompt < youpi> interestingly, atime is always 3-4 secs earlier than ctime & mtime < youpi> doesn't happen with dash < braunr> we should implement relatime and experiment with it < braunr> it shouldn't be hard < youpi> well, there's noatime already < youpi> but my point is that this update shouldn't happen < youpi> and I believe it's the source of the i_file_acl e2fsck warning < braunr> i wasn't saying that concerning this problem, it was just a separate idea (noatime is more problematic than relatime) < braunr> and i agree, it shouldn't happen :) < youpi> ok, it's set_node_times which gets called IRC, freenode, #hurd, 2011-07-27 < antrik> BTW, I'm not sure it's still relevant; but the reason accessing translators such as the console modifies the underlying node is that most stat information is generally passed through < antrik> (in some cases it might be unintentional though, simply using the default implementation from trivfs carelessly...) < youpi> I know < youpi> I've seen that in the code < antrik> OK < youpi> it is still relevant: I still find it useless to write it on the disk < youpi> though w uses it to show idle time over reboot < braunr> is it useful to keep the information across reboots ? < youpi> for some value of "useful" for w < braunr> i wonder what would break if this was entierly kept in memory < youpi> nothing, probably < youpi> note that it doesn't overload ext2fs so much, it just adds a write every ~5s < youpi> (at worse, i.e. when keeping showing text, for instance) < braunr> indeed, the behaviour seems the same on linux < antrik> ah... that explains why the disk doesn't spin down while IRC is active... always wondered about that :-) < youpi> that's not very power-saving, yes < youpi> well, we might want to put /dev on ram someday