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  1. 23 Jun, 2005 2 commits
    • Andrew Morton's avatar
      [PATCH] x86: cpu_khz type fix · a3a255e7
      Andrew Morton authored
      x86_64's cpu_khz is unsigned int and there is no reason why x86 needs to use
      unsigned long.
      
      So make cpu_khz unsigned int on x86 as well.
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      a3a255e7
    • Venkatesh Pallipadi's avatar
      [PATCH] Platform SMIs and their interferance with tsc based delay calibration · 8a9e1b0f
      Venkatesh Pallipadi authored
      Issue:
      Current tsc based delay_calibration can result in significant errors in
      loops_per_jiffy count when the platform events like SMIs
      (System Management Interrupts that are non-maskable) are present. This could
      lead to potential kernel panic(). This issue is becoming more visible with 2.6
      kernel (as default HZ is 1000) and on platforms with higher SMI handling
      latencies. During the boot time, SMIs are mostly used by BIOS (for things
      like legacy keyboard emulation).
      
      Description:
      The psuedocode for current delay calibration with tsc based delay looks like
      (0) Estimate a value for loops_per_jiffy
      (1) While (loops_per_jiffy estimate is accurate enough)
      (2)   wait for jiffy transition (jiffy1)
      (3)   Note down current tsc (tsc1)
      (4)   loop until tsc becomes tsc1 + loops_per_jiffy
      (5)   check whether jiffy changed since jiffy1 or not and refine
      loops_per_jiffy estimate
      
      Consider the following cases
      Case 1:
      If SMIs happen between (2) and (3) above, we can end up with a
      loops_per_jiffy value that is too low. This results in shorted delays and
      kernel can panic () during boot (Mostly at IOAPIC timer initialization
      timer_irq_works() as we don't have enough timer interrupts in a specified
      interval).
      
      Case 2:
      If SMIs happen between (3) and (4) above, then we can end up with a
      loops_per_jiffy value that is too high. And with current i386 code, too
      high lpj value (greater than 17M) can result in a overflow in
      delay.c:__const_udelay() again resulting in shorter delay and panic().
      
      Solution:
      The patch below makes the calibration routine aware of asynchronous events
      like SMIs. We increase the delay calibration time and also identify any
      significant errors (greater than 12.5%) in the calibration and notify it to
      user.
      
      Patch below changes both i386 and x86-64 architectures to use this
      new and improved calibrate_delay_direct() routine.
      Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
      Signed-off-by: default avatarAdrian Bunk <bunk@stusta.de>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      8a9e1b0f
  2. 16 Apr, 2005 1 commit
    • Linus Torvalds's avatar
      Linux-2.6.12-rc2 · 1da177e4
      Linus Torvalds authored
      Initial git repository build. I'm not bothering with the full history,
      even though we have it. We can create a separate "historical" git
      archive of that later if we want to, and in the meantime it's about
      3.2GB when imported into git - space that would just make the early
      git days unnecessarily complicated, when we don't have a lot of good
      infrastructure for it.
      
      Let it rip!
      1da177e4