diff options
Diffstat (limited to 'open_issues')
| -rw-r--r-- | open_issues/performance.mdwn | 11 | ||||
| -rw-r--r-- | open_issues/performance/io_system.mdwn | 42 | ||||
| -rw-r--r-- | open_issues/performance/io_system/binutils_ld_64ksec.mdwn (renamed from open_issues/io_system_binutils_ld_64ksec.mdwn) | 2 | ||||
| -rw-r--r-- | open_issues/performance/io_system/binutils_ld_64ksec/test.tar.xz (renamed from open_issues/io_system_binutils_ld_64ksec/test.tar.xz) | bin | 378092 -> 378092 bytes |
4 files changed, 54 insertions, 1 deletions
diff --git a/open_issues/performance.mdwn b/open_issues/performance.mdwn new file mode 100644 index 00000000..3ffffa4d --- /dev/null +++ b/open_issues/performance.mdwn @@ -0,0 +1,11 @@ +[[!meta copyright="Copyright © 2010 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]]."]]"""]] + + * [[I/O System|io_system]] diff --git a/open_issues/performance/io_system.mdwn b/open_issues/performance/io_system.mdwn new file mode 100644 index 00000000..bf59b5df --- /dev/null +++ b/open_issues/performance/io_system.mdwn @@ -0,0 +1,42 @@ +[[!meta copyright="Copyright © 2008, 2009, 2010 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]]."]]"""]] + +[[!meta title="I/O System"]] + +[[!tag open_issue_hurd]] + +The most obvious reason for the Hurd feeling slow compared to mainstream +systems like GNU/Linux, is a low I/O system performance, in particular very +slow hard disk access. + +The reason for this slowness is lack and/or bad implementation of common +optimization techniques, like scheduling reads and writes to minimize head +movement; effective block caching; effective reads/writes to partial blocks; +reading/writing multiple blocks at once; and read-ahead. The +[[ext2_filesystem_server|hurd/translator/ext2fs]] might also need some +optimizations at a higher logical level. + +The goal of this project is to analyze the current situation, and implement/fix +various optimizations, to achieve significantly better disk performance. It +requires understanding the data flow through the various layers involved in +disk access on the Hurd ([[filesystem|hurd/virtual_file_system]], +[[pager|hurd/libpager]], driver), and general experience with +optimizing complex systems. That said, the killing feature we are definitely +missing is the read-ahead, and even a very simple implementation would bring +very big performance speedups. + +Here's a real use-case: [[binutils_ld_64ksec]]. + +Possible mentors: Samuel Thibault (youpi) + +Exercise: Look through all the code involved in disk I/O, and try something +easy to improve. It's quite likely though that you will find nothing obvious -- +in this case, please contact us about a different exercise task. diff --git a/open_issues/io_system_binutils_ld_64ksec.mdwn b/open_issues/performance/io_system/binutils_ld_64ksec.mdwn index 0484137a..60dca510 100644 --- a/open_issues/io_system_binutils_ld_64ksec.mdwn +++ b/open_issues/performance/io_system/binutils_ld_64ksec.mdwn @@ -16,7 +16,7 @@ It is taken from the [[binutils_testsuite]], `ld/ld-elf/sec64k.exp`, where this test may occasionally [[trigger a timeout|binutils_testsuite#64ksec]]. It is extracted from cdf7c161ebd4a934c9e705d33f5247fd52975612 sources, 2010-10-24. - $ wget -O - http://www.gnu.org/software/hurd/open_issues/io_system_binutils_ld_64ksec/test.tar.xz | xz -d | tar -x + $ wget -O - http://www.gnu.org/software/hurd/open_issues/performance/io_system/binutils_ld_64ksec/test.tar.xz | xz -d | tar -x $ cd test/ $ \time ./ld-new.stripped -o dump dump?.o dump??.o 0.00user 0.00system 2:46.11elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k diff --git a/open_issues/io_system_binutils_ld_64ksec/test.tar.xz b/open_issues/performance/io_system/binutils_ld_64ksec/test.tar.xz Binary files differindex 6d7c606c..6d7c606c 100644 --- a/open_issues/io_system_binutils_ld_64ksec/test.tar.xz +++ b/open_issues/performance/io_system/binutils_ld_64ksec/test.tar.xz |