Announcement

Collapse
No announcement yet.

Linux 2.6.37-rc1 Kernel Is Here; Can Build Without BKL

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • #11
    whats the difference between BKL and nonBKL ?
    any charts? tests? something?

    Comment


    • #12
      Originally posted by NomadDemon View Post
      whats the difference between BKL and nonBKL ?
      any charts? tests? something?
      Are you asking for an explanation or benchmarks?

      If you want an explanation, wikipedia under "giant lock" has an explanation that might help you understand it better.

      Comment


      • #13
        iam not native english, i already reed giant lock, but dont understand anything [nothing seems to be more clear]

        both, benchmarks and explanations

        Comment


        • #14
          Did anybody tried compiling without Big Kernel Lock, this is what I get:
          Code:
            CHK     include/linux/version.h
            UPD     include/linux/version.h
            CHK     include/generated/utsrelease.h
            UPD     include/generated/utsrelease.h
            HOSTCC  scripts/kallsyms
            CC      scripts/mod/empty.o
            HOSTCC  scripts/mod/mk_elfconfig
            MKELF   scripts/mod/elfconfig.h
            HOSTCC  scripts/mod/file2alias.o
            HOSTCC  scripts/mod/modpost.o
            HOSTCC  scripts/mod/sumversion.o
            HOSTCC  scripts/pnmtologo
            HOSTCC  scripts/conmakehash
            HOSTCC  scripts/bin2c
            HOSTLD  scripts/mod/modpost
            CC      kernel/bounds.s
            GEN     include/generated/bounds.h
            CC      arch/x86/kernel/asm-offsets.s
          In file included from /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/suspend_64.h:10:0,
                           from /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/suspend.h:4,
                           from arch/x86/kernel/asm-offsets_64.c:20,
                           from arch/x86/kernel/asm-offsets.c:4:
          /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/i387.h: In function ‘irq_ts_save’:
          /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/i387.h:324:2: error: implicit declaration of function ‘kernel_locked’
          make[1]: *** [arch/x86/kernel/asm-offsets.s] Error 1
          make: *** [prepare0] Error 2
          [root@phenon linux-2.6.37-rc1]# make
            CHK     include/linux/version.h
            CHK     include/generated/utsrelease.h
            CC      arch/x86/kernel/asm-offsets.s
          In file included from /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/suspend_64.h:10:0,
                           from /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/suspend.h:4,
                           from arch/x86/kernel/asm-offsets_64.c:20,
                           from arch/x86/kernel/asm-offsets.c:4:
          /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/i387.h: In function ‘irq_ts_save’:
          /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/i387.h:324:2: error: implicit declaration of function ‘kernel_locked’
          make[1]: *** [arch/x86/kernel/asm-offsets.s] Error 1
          make: *** [prepare0] Error 2
          [root@phenon linux-2.6.37-rc1]#

          Comment


          • #15
            Originally posted by NomadDemon View Post
            iam not native english, i already reed giant lock, but dont understand anything [nothing seems to be more clear]

            both, benchmarks and explanations
            A lock is a synchronization primitive. Basically you place it around blocks of code, and then it becomes impossible for 1 thread to enter the block until the first has exited. The idea is to keep 1 thread from deleting or modifying some shared data before another thread has finished using it. In a userspace program that is only an issue for multi-threaded applications. In the kernel, there are all sorts of threads, events, and hardware interrupts that can cause an issue.

            A long time ago, devs originally create 1 large lock and used it everywhere in the kernel. That was simple to do, because essentially grabbing the lock switched all the code inside into a single-threaded mode. But it has issues with scalability - you want as many different threads as possible able to work. There's no reason the memory subsystem and the Ext4 filesystem should both be blocking each other. So the solution is to create 2 locks, one for each section. The complication is that so much complicated code had come to rely on the single lock that it was almost impossible to predict the behavior of the kernel when you messed with that global lock. So people have been slowly going through section by section of the kernel to try and factor out what codes needs to share the same lock and what code can be separated out. A lot of the code under the global lock didn't even need to be, and was just there because the original coder thought it might be an issue.

            So I'm not really sure how benchmarks will change. It will definitely increase the scalability of anything that likes to hit a bunch of kernel code. But on the other hand, this has been going on piece by piece for many years. So a lot of the benefits were already done and in previous kernels.

            Comment


            • #16
              Originally posted by hax0r View Post
              Did anybody tried compiling without Big Kernel Lock, this is what I get:
              Code:
                CHK     include/linux/version.h
                UPD     include/linux/version.h
                CHK     include/generated/utsrelease.h
                UPD     include/generated/utsrelease.h
                HOSTCC  scripts/kallsyms
                CC      scripts/mod/empty.o
                HOSTCC  scripts/mod/mk_elfconfig
                MKELF   scripts/mod/elfconfig.h
                HOSTCC  scripts/mod/file2alias.o
                HOSTCC  scripts/mod/modpost.o
                HOSTCC  scripts/mod/sumversion.o
                HOSTCC  scripts/pnmtologo
                HOSTCC  scripts/conmakehash
                HOSTCC  scripts/bin2c
                HOSTLD  scripts/mod/modpost
                CC      kernel/bounds.s
                GEN     include/generated/bounds.h
                CC      arch/x86/kernel/asm-offsets.s
              In file included from /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/suspend_64.h:10:0,
                               from /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/suspend.h:4,
                               from arch/x86/kernel/asm-offsets_64.c:20,
                               from arch/x86/kernel/asm-offsets.c:4:
              /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/i387.h: In function ‘irq_ts_save’:
              /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/i387.h:324:2: error: implicit declaration of function ‘kernel_locked’
              make[1]: *** [arch/x86/kernel/asm-offsets.s] Error 1
              make: *** [prepare0] Error 2
              [root@phenon linux-2.6.37-rc1]# make
                CHK     include/linux/version.h
                CHK     include/generated/utsrelease.h
                CC      arch/x86/kernel/asm-offsets.s
              In file included from /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/suspend_64.h:10:0,
                               from /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/suspend.h:4,
                               from arch/x86/kernel/asm-offsets_64.c:20,
                               from arch/x86/kernel/asm-offsets.c:4:
              /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/i387.h: In function ‘irq_ts_save’:
              /usr/src/linux-2.6.37-rc1/arch/x86/include/asm/i387.h:324:2: error: implicit declaration of function ‘kernel_locked’
              make[1]: *** [arch/x86/kernel/asm-offsets.s] Error 1
              make: *** [prepare0] Error 2
              [root@phenon linux-2.6.37-rc1]#
              I get the same error....

              Comment

              Working...
              X