Package: mysql-server-core-5.5 Version: 5.5.23-2 Severity: normal The MySQL server wakes up several times per second even if no clients are connected. Waking up the CPU unnecessarily results in increased power consumption. Please consider allowing mysqld to sleep until it has queries to process.
Here is the result of tracing all threads of idle mysqld for 4 seconds: # for i in /proc/$(pidof mysqld)/task/*; do timeout -s INT 4 strace -p $(basename $i); done Process 11711 attached - interrupt to quit restart_syscall(<... resuming interrupted call ...> <unfinished ...> Process 11711 detached Process 11731 attached - interrupt to quit io_getevents(-202268672, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202268672, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202268672, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202268672, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202268672, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202268672, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202268672, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202268672, 1, 256, <unfinished ...> Process 11731 detached Process 11732 attached - interrupt to quit io_getevents(-202280960, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202280960, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202280960, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202280960, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202280960, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202280960, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202280960, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202280960, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202280960, 1, 256, <unfinished ...> Process 11732 detached Process 11733 attached - interrupt to quit io_getevents(-202428416, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202428416, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202428416, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202428416, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202428416, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202428416, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202428416, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202428416, 1, 256, <unfinished ...> Process 11733 detached Process 11734 attached - interrupt to quit io_getevents(-202440704, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202440704, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202440704, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202440704, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202440704, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202440704, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202440704, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202440704, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202440704, 1, 256, <unfinished ...> Process 11734 detached Process 11735 attached - interrupt to quit io_getevents(-202452992, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202452992, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202452992, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202452992, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202452992, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202452992, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202452992, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202452992, 1, 256, <unfinished ...> Process 11735 detached Process 11736 attached - interrupt to quit io_getevents(-202465280, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202465280, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202465280, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202465280, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202465280, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202465280, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202465280, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202465280, 1, 256, <unfinished ...> Process 11736 detached Process 11737 attached - interrupt to quit io_getevents(-202612736, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202612736, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202612736, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202612736, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202612736, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202612736, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202612736, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202612736, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202612736, 1, 256, <unfinished ...> Process 11737 detached Process 11738 attached - interrupt to quit io_getevents(-202625024, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202625024, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202625024, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202625024, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202625024, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202625024, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202625024, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202625024, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202625024, 1, 256, <unfinished ...> Process 11738 detached Process 11739 attached - interrupt to quit io_getevents(-202637312, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202637312, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202637312, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202637312, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202637312, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202637312, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202637312, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202637312, 1, 256, <unfinished ...> Process 11739 detached Process 11740 attached - interrupt to quit io_getevents(-202649600, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202649600, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202649600, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202649600, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202649600, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202649600, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202649600, 1, 256, {}{0, 500000000}) = 0 io_getevents(-202649600, 1, 256, <unfinished ...> Process 11740 detached Process 11742 attached - interrupt to quit restart_syscall(<... resuming interrupted call ...>) = -1 ETIMEDOUT (Connection timed out) futex(0xf7fee5f0, FUTEX_WAKE_PRIVATE, 1) = 0 gettimeofday({1336846019, 586801}, NULL) = 0 clock_gettime(CLOCK_REALTIME, {1336846019, 586944765}) = 0 futex(0xf7fee618, FUTEX_WAIT_PRIVATE, 505, {0, 999856235}) = -1 ETIMEDOUT (Connection timed out) futex(0xf7fee5f0, FUTEX_WAKE_PRIVATE, 1) = 0 gettimeofday({1336846020, 587593}, NULL) = 0 clock_gettime(CLOCK_REALTIME, {1336846020, 587759623}) = 0 futex(0xf7fee618, FUTEX_WAIT_PRIVATE, 507, {0, 999833377}) = -1 ETIMEDOUT (Connection timed out) futex(0xf7fee5f0, FUTEX_WAKE_PRIVATE, 1) = 0 gettimeofday({1336846021, 588515}, NULL) = 0 clock_gettime(CLOCK_REALTIME, {1336846021, 588691875}) = 0 futex(0xf7fee618, FUTEX_WAIT_PRIVATE, 509, {0, 999823125}) = -1 ETIMEDOUT (Connection timed out) futex(0xf7fee5f0, FUTEX_WAKE_PRIVATE, 1) = 0 gettimeofday({1336846022, 589312}, NULL) = 0 clock_gettime(CLOCK_REALTIME, {1336846022, 589488639}) = 0 futex(0xf7fee618, FUTEX_WAIT_PRIVATE, 511, {0, 999823361} <unfinished ...> Process 11742 detached Process 11743 attached - interrupt to quit restart_syscall(<... resuming interrupted call ...>) = -1 ETIMEDOUT (Connection timed out) futex(0xf7fee590, FUTEX_WAKE_PRIVATE, 1) = 0 time(NULL) = 1336846023 gettimeofday({1336846023, 667902}, NULL) = 0 clock_gettime(CLOCK_REALTIME, {1336846023, 668036084}) = 0 futex(0xf7fee5b8, FUTEX_WAIT_PRIVATE, 513, {0, 999865916}) = -1 ETIMEDOUT (Connection timed out) futex(0xf7fee590, FUTEX_WAKE_PRIVATE, 1) = 0 time(NULL) = 1336846024 gettimeofday({1336846024, 669045}, NULL) = 0 clock_gettime(CLOCK_REALTIME, {1336846024, 669187950}) = 0 futex(0xf7fee5b8, FUTEX_WAIT_PRIVATE, 515, {0, 999857050}) = -1 ETIMEDOUT (Connection timed out) futex(0xf7fee590, FUTEX_WAKE_PRIVATE, 1) = 0 time(NULL) = 1336846025 gettimeofday({1336846025, 669988}, NULL) = 0 clock_gettime(CLOCK_REALTIME, {1336846025, 670071788}) = 0 futex(0xf7fee5b8, FUTEX_WAIT_PRIVATE, 517, {0, 999916212}) = -1 ETIMEDOUT (Connection timed out) futex(0xf7fee590, FUTEX_WAKE_PRIVATE, 1) = 0 time(NULL) = 1336846026 gettimeofday({1336846026, 671174}, NULL) = 0 clock_gettime(CLOCK_REALTIME, {1336846026, 671318058}) = 0 futex(0xf7fee5b8, FUTEX_WAIT_PRIVATE, 519, {0, 999855942} <unfinished ...> Process 11743 detached Process 11744 attached - interrupt to quit restart_syscall(<... resuming interrupted call ...>) = -1 ETIMEDOUT (Connection timed out) futex(0xf7fee650, FUTEX_WAKE_PRIVATE, 1) = 0 time(NULL) = 1336846027 time(NULL) = 1336846027 gettimeofday({1336846027, 523539}, NULL) = 0 clock_gettime(CLOCK_REALTIME, {1336846027, 523729853}) = 0 futex(0xf7fee678, FUTEX_WAIT_PRIVATE, 105, {4, 999809147} <unfinished ...> Process 11744 detached Process 11745 attached - interrupt to quit futex(0xf7e199b8, FUTEX_WAIT_PRIVATE, 1, NULL <unfinished ...> Process 11745 detached Process 11746 attached - interrupt to quit rt_sigtimedwait([HUP QUIT ALRM TERM TSTP], NULL, NULL, 8 <unfinished ...> Process 11746 detached # -- System Information: Debian Release: wheezy/sid APT prefers testing APT policy: (500, 'testing'), (400, 'unstable'), (300, 'experimental') Architecture: i386 (x86_64) Kernel: Linux 3.3.5 (SMP w/2 CPU cores) Locale: LANG=C.UTF-8, LC_CTYPE=C.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Versions of packages mysql-server-core-5.5 depends on: ii libaio1 0.3.109-2 ii libc6 2.13-32 ii libgcc1 1:4.7.0-7 ii libssl1.0.0 1.0.1b-1 ii libstdc++6 4.7.0-7 ii libwrap0 7.6.q-23 ii zlib1g 1:1.2.6.dfsg-2 mysql-server-core-5.5 recommends no packages. mysql-server-core-5.5 suggests no packages. -- no debconf information -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". 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