diff options
Diffstat (limited to 'meta/recipes-kernel/systemtap/systemtap/0001-PR28804-tune-default-stap-s-buffer-size-on-small-RAM.patch')
| -rw-r--r-- | meta/recipes-kernel/systemtap/systemtap/0001-PR28804-tune-default-stap-s-buffer-size-on-small-RAM.patch | 84 |
1 files changed, 0 insertions, 84 deletions
diff --git a/meta/recipes-kernel/systemtap/systemtap/0001-PR28804-tune-default-stap-s-buffer-size-on-small-RAM.patch b/meta/recipes-kernel/systemtap/systemtap/0001-PR28804-tune-default-stap-s-buffer-size-on-small-RAM.patch deleted file mode 100644 index 931310db53..0000000000 --- a/meta/recipes-kernel/systemtap/systemtap/0001-PR28804-tune-default-stap-s-buffer-size-on-small-RAM.patch +++ /dev/null @@ -1,84 +0,0 @@ -Upstream-Status: Backport -Signed-off-by: Ross Burton <ross.burton@arm.com> - -PR28804: tune default stap -s ## buffer size on small RAM machines - -Insert a forgotten division by num_online_cpu() to adjust downward the -calculated bufsize. Tweak normal defaults back to 128 * 2 * 64K -(16MB) per CPU, as the stap man page indicates. This may need further -tweaking when balancing against staprun consumption performance, but -at least we have the docs lined up with the code at the moment. - -PR28804: tune default stap -s ## buffer size on small RAM machines - -Use si_meminfo to limit default buffer size. Note in the man page -that the "-s ##" parameter is per-CPU. - -diff --git a/man/stap.1.in b/man/stap.1.in -index 55dbc2c93..285a27b34 100644 ---- a/man/stap.1.in -+++ b/man/stap.1.in -@@ -239,8 +239,8 @@ and average amount of time spent in each probe-point. Also shows - the derivation for each probe-point. - .TP - .BI \-s " NUM" --Use NUM megabyte buffers for kernel-to-user data transfer. On a --multiprocessor in bulk mode, this is a per-processor amount. -+Use NUM megabyte buffers for kernel-to-user data transfer per processor. -+The default is 16MB, or less on smaller memory machines. - .TP - .BI \-I " DIR" - Add the given directory to the tapset search directory. See the -diff --git a/runtime/transport/transport.c b/runtime/transport/transport.c -index 18ecccea2..44afff814 100644 ---- a/runtime/transport/transport.c -+++ b/runtime/transport/transport.c -@@ -72,8 +72,11 @@ static inline void _stp_unlock_inode(struct inode *inode); - #include "procfs.c" - #include "control.c" - --static unsigned _stp_nsubbufs = 256; --static unsigned _stp_subbuf_size = 8 * STP_BUFFER_SIZE; /* 64K */ -+/* set default buffer parameters. User may override these via stap -s #, and -+ the runtime may auto-shrink it on low memory machines too. */ -+/* NB: Note default in man/stap.1.in */ -+static unsigned _stp_nsubbufs = 128; -+static unsigned _stp_subbuf_size = 2 * STP_BUFFER_SIZE; /* 2 * 64K */ - - /* module parameters */ - static int _stp_bufsize; -@@ -602,17 +605,30 @@ static int _stp_transport_init(void) - _stp_need_kallsyms_stext = 0; - #endif - -- if (_stp_bufsize) { -- unsigned size = _stp_bufsize * 1024 * 1024; -+ if (_stp_bufsize == 0) { // option not specified? -+ struct sysinfo si; -+ long _stp_bufsize_avail; -+ si_meminfo(&si); -+ _stp_bufsize_avail = (long)((si.freeram + si.bufferram) / 4 / num_online_cpus()) -+ << PAGE_SHIFT; // limit to quarter of free ram total -+ if ((_stp_nsubbufs * _stp_subbuf_size * num_online_cpus()) > _stp_bufsize_avail) { -+ _stp_bufsize = max_t (int, 1, _stp_bufsize_avail / 1024 / 1024); -+ dbug_trans(1, "Shrinking default _stp_bufsize to %d MB/cpu due to low free memory\n", _stp_bufsize); -+ } -+ } -+ -+ if (_stp_bufsize) { // overridden by user or by si_meminfo heuristic? -+ long size = _stp_bufsize * 1024 * 1024; - _stp_subbuf_size = 65536; -+ // bump up subbuf size from 64K to 1M to keep _stp_nsubbufs not too large - while (size / _stp_subbuf_size > 64 && - _stp_subbuf_size < 1024 * 1024) { - _stp_subbuf_size <<= 1; - } - _stp_nsubbufs = size / _stp_subbuf_size; -- dbug_trans(1, "Using %d subbufs of size %d\n", _stp_nsubbufs, _stp_subbuf_size); - } -- -+ dbug_trans(1, "Using %d subbufs of size %d\n", _stp_nsubbufs, _stp_subbuf_size); -+ - ret = _stp_transport_fs_init(THIS_MODULE->name); - if (ret) - goto err0; |