- 22 May, 2022 1 commit
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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 ...
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- 27 Oct, 2020 1 commit
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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:
zhenwei pi <pizhenwei@bytedance.com>
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- 24 Oct, 2019 1 commit
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Oran Agra authored
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- 11 Feb, 2015 1 commit
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antirez authored
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- 12 Nov, 2014 1 commit
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antirez authored
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- 08 Jul, 2014 1 commit
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antirez authored
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- 07 Jul, 2014 1 commit
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antirez authored
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- 02 Jul, 2014 3 commits
- 01 Jul, 2014 3 commits
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antirez authored
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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.
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antirez authored
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