diff options
Diffstat (limited to 'stap.1.in')
| -rw-r--r-- | stap.1.in | 27 |
1 files changed, 21 insertions, 6 deletions
@@ -230,6 +230,9 @@ nor the kernel debugging information can be found. .TP .B \-\-ignore\-dwarf For testing, act as though vmlinux and modules lack debugging information. +.TP +.B \-\-skip\-badvars +Ignore out of context variables and substitute with literal 0. .SH ARGUMENTS @@ -1039,10 +1042,10 @@ Maximum number of soft errors before an exit is triggered, default 0, which means that the first error will exit the script. .TP MAXSKIPPED -.TP Maximum number of skipped probes before an exit is triggered, default 100. Running systemtap with \-t (timing) mode gives more details about skipped probes. +.TP MINSTACKSPACE Minimum number of free kernel stack bytes required in order to run a probe handler, default 1024. This number should be large enough @@ -1053,8 +1056,20 @@ Maximum number of concurrently armed user-space probes (uprobes), default 100 times the number of user-space probe points named in the script. This pool is large because individual uprobe objects are allocated for each process for each script-level probe. + .PP -Multipule scripts can write data into a relay buffer concurrently. A host +With scripts that contain probes on any interrupt path, it is possible that +those interrupts may occur in the middle of another probe handler. The probe +in the interrupt handler would be skipped in this case to avoid reentrance. +To work around this issue, execute stap with the option +.BR \-DINTERRUPTIBLE=0 +to mask interrupts throughout the probe handler. This does add some extra +overhead to the probes, but it may prevent reentrance for common problem +cases. However, probes in NMI handlers and in the callpath of the stap +runtime may still be skipped due to reentrance. + +.PP +Multiple scripts can write data into a relay buffer concurrently. A host script provides an interface for accessing its relay buffer to guest scripts. Then, the output of the guests are merged into the output of the host. To run a script as a host, execute stap with @@ -1096,16 +1111,16 @@ using symbols read from vmlinux and/or the modules in /lib/modules. Systemtap can also read the kernel symbol table from a text file such as /boot/System.map or /proc/kallsyms. See the -.B \-\--kelf +.B \-\-kelf and -.B \-\--kmap +.B \-\-kmap options. .PP If systemtap finds relevant debugging information, it will use it even if you specify -.B \-\--kelf +.B \-\-kelf or -.BR \-\--kmap . +.BR \-\-kmap . .PP Without debugging information, systemtap cannot support the following types of language constructs: |