RHEL7: Intermittent system performance slowness
Issue
- Application response time slows intermittently for long seconds (few seconds to 20 seconds) compared with sub second to a second response time
- Application times out intermittently failing to respond in a timely manner
Environment
- Red Hat Enterprise Linux (RHEL) 7.4, 7.5, 7.6.
- Server is using uEFI boot and has ACPI BGRT data (/sys/firmware/acpi/bgrt/image)
- Below mentioned similar warning logs might be observed :
[ 0.325420] ------------[ cut here ]------------
[ 0.325426] WARNING: CPU: 0 PID: 0 at arch/x86/mm/ioremap.c:119 __ioremap_caller+0x279/0x320
[ 0.325428] ioremap on RAM at 0xc5f51018 - 0xc5f5101d
[ 0.325429] Modules linked in:
[ 0.325432] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.10.0-693.el7.x86_64 #1
[ 0.325433] Hardware name: XXX
[ 0.325434] ffffffff819e7e38 24c6cdef24c6cdb8 ffffffff819e7de8 ffffffff816a3d91
[ 0.325437] ffffffff819e7e28 ffffffff810879c8 00000077c5f51fff 00000000c5f5101d
[ 0.325439] 0000000000000006 00000000c5f5101e 0000000000000010 00000000c5f51018
[ 0.325441] Call Trace:
[ 0.325446] [<ffffffff816a3d91>] dump_stack+0x19/0x1b
[ 0.325449] [<ffffffff810879c8>] __warn+0xd8/0x100
[ 0.325451] [<ffffffff81087a4f>] warn_slowpath_fmt+0x5f/0x80
[ 0.325454] [<ffffffff81067fe9>] __ioremap_caller+0x279/0x320
[ 0.325457] [<ffffffff813c95da>] ? acpi_tb_validate_table+0x27/0x37
[ 0.325461] [<ffffffff81b668e4>] ? efi_bgrt_init+0x6c/0x108
[ 0.325463] [<ffffffff810680a7>] ioremap_nocache+0x17/0x20
[ 0.325465] [<ffffffff81b668e4>] efi_bgrt_init+0x6c/0x108
[ 0.325467] [<ffffffff81b65d2e>] efi_late_init+0x13/0x15
[ 0.325470] [<ffffffff81b45051>] start_kernel+0x42a/0x45a
[ 0.325471] [<ffffffff81b44a30>] ? repair_env_string+0x5c/0x5c
[ 0.325474] [<ffffffff81b44120>] ? early_idt_handler_array+0x120/0x120
[ 0.325476] [<ffffffff81b445ef>] x86_64_start_reservations+0x24/0x26
[ 0.325478] [<ffffffff81b44740>] x86_64_start_kernel+0x14f/0x172
[ 0.325481] ---[ end trace 25a5ba0f2a13fe13 ]---
OR
Mar 6 15:54:53 localhost kernel: ------------[ cut here ]------------
Mar 6 15:54:53 localhost kernel: WARNING: CPU: 0 PID: 0 at arch/x86/mm/ioremap.c:115 __ioremap_caller+0x179/0x340
Mar 6 15:54:53 localhost kernel: ioremap on RAM at 0x86f12018 - 0x86f1201d
Mar 6 15:54:53 localhost kernel: Modules linked in:
Mar 6 15:54:53 localhost kernel: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.10.0-862.el7.x86_64 #1
Mar 6 15:54:53 localhost kernel: Hardware name: XXX
Mar 6 15:54:53 localhost kernel: Call Trace:
Mar 6 15:54:53 localhost kernel: [<ffffffff81b0d768>] dump_stack+0x19/0x1b
Mar 6 15:54:53 localhost kernel: [<ffffffff814916d8>] __warn+0xd8/0x100
Mar 6 15:54:53 localhost kernel: [<ffffffff8149175f>] warn_slowpath_fmt+0x5f/0x80
Mar 6 15:54:53 localhost kernel: [<ffffffff8146f2c9>] __ioremap_caller+0x179/0x340
Mar 6 15:54:53 localhost kernel: [<ffffffff82190243>] ? efi_bgrt_init+0x6c/0x108
Mar 6 15:54:53 localhost kernel: [<ffffffff8146f4a7>] ioremap_nocache+0x17/0x20
Mar 6 15:54:53 localhost kernel: [<ffffffff82190243>] efi_bgrt_init+0x6c/0x108
Mar 6 15:54:53 localhost kernel: [<ffffffff8218f541>] efi_late_init+0x13/0x15
Mar 6 15:54:53 localhost kernel: [<ffffffff8216c1b2>] start_kernel+0x437/0x467
Mar 6 15:54:53 localhost kernel: [<ffffffff8216bb7b>] ? repair_env_string+0x5c/0x5c
Mar 6 15:54:53 localhost kernel: [<ffffffff8216b120>] ? early_idt_handler_array+0x120/0x120
Mar 6 15:54:53 localhost kernel: [<ffffffff8216b72f>] x86_64_start_reservations+0x24/0x26
Mar 6 15:54:53 localhost kernel: [<ffffffff8216b885>] x86_64_start_kernel+0x154/0x177
Mar 6 15:54:53 localhost kernel: [<ffffffff814000d5>] start_cpu+0x5/0x14
Mar 6 15:54:53 localhost kernel: ---[ end trace b44fe2afc20dad9d ]---
Mar 6 15:54:53 localhost kernel: Ignoring BGRT: failed to map image header memory
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