in the context of seamless reload and busy polling, older processes will create unecessary cpu conflicts; we can assume there is no need for busy polling for old processes which are waiting to be terminated.
This patch is not a bug fix itself but might be a good stability improvment when you are un the context of frequent seamless reloads with a high "hard-stop-after" value; for that reasons I think this patch should be backported in all 2.x versions. Signed-off-by: William Dauchy <[email protected]> --- doc/configuration.txt | 3 +++ src/proxy.c | 2 ++ 2 files changed, 5 insertions(+) diff --git a/doc/configuration.txt b/doc/configuration.txt index bfc8b903..c8e13192 100644 --- a/doc/configuration.txt +++ b/doc/configuration.txt @@ -1475,6 +1475,9 @@ busy-polling default. If it has been enabled, it may still be forcibly disabled by prefixing it with the "no" keyword. It is ignored by the "select" and "poll" pollers. + This option is automatically disabled on old processes in the context of + seamless reload; it avoids too much cpu conflicts when multiple processes + stay around for some time waiting for the end of their current connections. max-spread-checks <delay in milliseconds> By default, haproxy tries to spread the start of health checks across the diff --git a/src/proxy.c b/src/proxy.c index a5570daf..9448d1a3 100644 --- a/src/proxy.c +++ b/src/proxy.c @@ -1116,6 +1116,8 @@ void soft_stop(void) struct task *task; stopping = 1; + /* disable busy polling to avoid cpu eating for the new process */ + global.tune.options &= ~GTUNE_BUSY_POLLING; if (tick_isset(global.hard_stop_after)) { task = task_new(MAX_THREADS_MASK); if (task) { -- 2.24.1
