1. 22 May, 2022 1 commit
    • yoav-steinberg's avatar
      Add warning for suspected slow system clocksource setting (#10636) · 843a4cdc
      yoav-steinberg authored
      This PR does 2 main things:
      1) Add warning for suspected slow system clocksource setting. This is Linux specific.
      2) Add a `--check-system` argument to redis which runs all system checks and prints a report.
      
      ## System checks
      Add a command line option `--check-system` which runs all known system checks and provides
      a report to stdout of which systems checks have failed with details on how to reconfigure the
      system for optimized redis performance.
      The `--system-check` mode exists with an appropriate error code after running all the checks.
      
      ## Slow clocksource details
      We check the system's clocksource performance by running `clock_gettime()` in a loop and then
      checking how much time was spent in a system call (via `getrusage()`). If we spend more than
      10% of the time in the kernel then we print a warning. I verified that using the slow clock sources:
      `acpi_pm` (~90% in the kernel on my laptop) and `xen` (~30% in the kernel on ...
      843a4cdc
  2. 27 Oct, 2020 1 commit
    • zhenwei pi's avatar
      Disable THP if enabled (#7381) · a9c06021
      zhenwei pi authored
      In case redis starts and find that THP is enabled ("always"), instead
      of printing a log message, which might go unnoticed, redis will try to
      disable it (just for the redis process).
      
      Note: it looks like on self-bulit kernels THP is likely be set to "always" by default.
      
      Some discuss about THP side effect on Linux:
      according to http://www.antirez.com/news/84
      
      , we can see that
      redis latency spikes are caused by linux kernel THP feature.
      I have tested on E3-2650 v3, and found that 2M huge page costs
      about 0.25ms to fix COW page fault.
      
      Add a new config 'disable-thp', the recommended setting is 'yes',
      (default) the redis tries to disable THP by prctl syscall. But
      users who really want THP can set it to "no"
      
      Thanks to Oran & Yossi for suggestions.
      Signed-off-by: default avatarzhenwei pi <pizhenwei@bytedance.com>
      a9c06021
  3. 24 Oct, 2019 1 commit
  4. 11 Feb, 2015 1 commit
  5. 12 Nov, 2014 1 commit
  6. 08 Jul, 2014 1 commit
  7. 07 Jul, 2014 1 commit
  8. 02 Jul, 2014 3 commits
  9. 01 Jul, 2014 3 commits
    • antirez's avatar
      753b707d
    • antirez's avatar
      Latency monitor: collect slow commands. · 8612e6de
      antirez authored
      We introduce the distinction between slow and fast commands since those
      are two different sources of latency. An O(1) or O(log N) command without
      side effects (can't trigger deletion of large objects as a side effect of
      its execution) if delayed is a symptom of inherent latency of the system.
      
      A non-fast command (commands that may run large O(N) computations) if
      delayed may just mean that the user is executing slow operations.
      
      The advices LATENCY should provide in this two different cases are
      different, so we log the two classes of commands in a separated way.
      8612e6de
    • antirez's avatar
      Latency monitor: basic samples collection. · d7a07a20
      antirez authored
      d7a07a20