* About using PEBS from the user space @ 2015-05-03 22:05 Harald Servat 2015-05-03 22:19 ` Vince Weaver 0 siblings, 1 reply; 7+ messages in thread From: Harald Servat @ 2015-05-03 22:05 UTC (permalink / raw) To: linux-perf-users Dear list, I'd like to use the perf library to access PEBS so as to collect referenced memory addresses from the user space. I think I've successfully setup the perf structures (struct perf_event_attr) to configure the performance counters, but I don't see what should I do to access to the captured memory addresses. I've seen that within arch/x86/kernel/cpu/perf_event_intel_ds.c there are the routines alloc_pebs_buffer, alloc_ds_buffer which seems to allocate and setup the necessary buffers using kmalloc_node calls. Question is, how can replicate this from the user space? And how we should connect these buffers to the PEBS infrastructure using perf calls? Thank you very much in advance. WARNING / LEGAL TEXT: This message is intended only for the use of the individual or entity to which it is addressed and may contain information which is privileged, confidential, proprietary, or exempt from disclosure under applicable law. If you are not the intended recipient or the person responsible for delivering the message to the intended recipient, you are strictly prohibited from disclosing, distributing, copying, or in any way using this message. If you have received this communication in error, please notify the sender and destroy and delete any copies you may have received. http://www.bsc.es/disclaimer ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: About using PEBS from the user space 2015-05-03 22:05 About using PEBS from the user space Harald Servat @ 2015-05-03 22:19 ` Vince Weaver 2015-05-04 8:13 ` Harald Servat ` (2 more replies) 0 siblings, 3 replies; 7+ messages in thread From: Vince Weaver @ 2015-05-03 22:19 UTC (permalink / raw) To: Harald Servat; +Cc: linux-perf-users On Mon, 4 May 2015, Harald Servat wrote: > Dear list, > > I'd like to use the perf library to access PEBS so as to collect referenced > memory addresses from the user space. I think I've successfully setup the perf > structures (struct perf_event_attr) to configure the performance counters, but > I don't see what should I do to access to the captured memory addresses. I've > seen that within arch/x86/kernel/cpu/perf_event_intel_ds.c there are the > routines alloc_pebs_buffer, alloc_ds_buffer which seems to allocate and setup > the necessary buffers using kmalloc_node calls. Question is, how can replicate > this from the user space? And how we should connect these buffers to the PEBS > infrastructure using perf calls? You can try looking at the example code in my perf_event_tests code. https://github.com/deater/perf_event_tests The stuff you are looking for is probably covered in the test/record_sample/samples_data_src test/record_sample/sample_weight and especially the test/record_sample/sample_regs_intr tests, although that last one requires a fairly recent kernel to work. Vince ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: About using PEBS from the user space 2015-05-03 22:19 ` Vince Weaver @ 2015-05-04 8:13 ` Harald Servat 2015-05-04 10:17 ` Harald Servat 2015-06-25 16:00 ` Harald Servat 2 siblings, 0 replies; 7+ messages in thread From: Harald Servat @ 2015-05-04 8:13 UTC (permalink / raw) To: Vince Weaver; +Cc: linux-perf-users On 04/05/15 00:19, Vince Weaver wrote: > On Mon, 4 May 2015, Harald Servat wrote: > >> Dear list, >> >> I'd like to use the perf library to access PEBS so as to collect referenced >> memory addresses from the user space. I think I've successfully setup the perf >> structures (struct perf_event_attr) to configure the performance counters, but >> I don't see what should I do to access to the captured memory addresses. I've >> seen that within arch/x86/kernel/cpu/perf_event_intel_ds.c there are the >> routines alloc_pebs_buffer, alloc_ds_buffer which seems to allocate and setup >> the necessary buffers using kmalloc_node calls. Question is, how can replicate >> this from the user space? And how we should connect these buffers to the PEBS >> infrastructure using perf calls? > > You can try looking at the example code in my perf_event_tests code. > https://github.com/deater/perf_event_tests > > The stuff you are looking for is probably covered in the > test/record_sample/samples_data_src > test/record_sample/sample_weight > and especially the > test/record_sample/sample_regs_intr > tests, although that last one requires a fairly recent kernel to work. > > Vince Thank you very much for these pointers Vince. I'll take a look at them! Best regards. WARNING / LEGAL TEXT: This message is intended only for the use of the individual or entity to which it is addressed and may contain information which is privileged, confidential, proprietary, or exempt from disclosure under applicable law. If you are not the intended recipient or the person responsible for delivering the message to the intended recipient, you are strictly prohibited from disclosing, distributing, copying, or in any way using this message. If you have received this communication in error, please notify the sender and destroy and delete any copies you may have received. http://www.bsc.es/disclaimer ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: About using PEBS from the user space 2015-05-03 22:19 ` Vince Weaver 2015-05-04 8:13 ` Harald Servat @ 2015-05-04 10:17 ` Harald Servat 2015-06-25 16:00 ` Harald Servat 2 siblings, 0 replies; 7+ messages in thread From: Harald Servat @ 2015-05-04 10:17 UTC (permalink / raw) To: Vince Weaver; +Cc: linux-perf-users [-- Attachment #1: Type: text/plain, Size: 3669 bytes --] On 04/05/15 00:19, Vince Weaver wrote: > On Mon, 4 May 2015, Harald Servat wrote: > >> Dear list, >> >> I'd like to use the perf library to access PEBS so as to collect referenced >> memory addresses from the user space. I think I've successfully setup the perf >> structures (struct perf_event_attr) to configure the performance counters, but >> I don't see what should I do to access to the captured memory addresses. I've >> seen that within arch/x86/kernel/cpu/perf_event_intel_ds.c there are the >> routines alloc_pebs_buffer, alloc_ds_buffer which seems to allocate and setup >> the necessary buffers using kmalloc_node calls. Question is, how can replicate >> this from the user space? And how we should connect these buffers to the PEBS >> infrastructure using perf calls? > > You can try looking at the example code in my perf_event_tests code. > https://github.com/deater/perf_event_tests > > The stuff you are looking for is probably covered in the > test/record_sample/samples_data_src > test/record_sample/sample_weight > and especially the > test/record_sample/sample_regs_intr > tests, although that last one requires a fairly recent kernel to work. > > Vince Vince, that is really interesting work, thank you! However, for some reason the PEBS collected address is never shown (and maybe not captured) according to the following partial output PERF_RECORD_SAMPLE [c001], MISC=16386 (PERF_RECORD_MISC_USER,PERF_RECORD_MISC_EXACT_IP ), Size=32 PERF_SAMPLE_IP, IP: 404510 PERF_SAMPLE_WEIGHT, Weight: 30 PERF_SAMPLE_DATA_SRC, Raw: 68100242 Load Hit Line fill buffer No snoop Hit Level 1 TLB Level 2 TLB PERF_RECORD_SAMPLE [c001], MISC=16386 (PERF_RECORD_MISC_USER,PERF_RECORD_MISC_EXACT_IP ), Size=32 PERF_SAMPLE_IP, IP: 404524 PERF_SAMPLE_WEIGHT, Weight: 76 PERF_SAMPLE_DATA_SRC, Raw: 68100442 Load Hit L2 cache No snoop Hit Level 1 TLB Level 2 TLB PERF_RECORD_SAMPLE [c001], MISC=16386 (PERF_RECORD_MISC_USER,PERF_RECORD_MISC_EXACT_IP ), Size=32 PERF_SAMPLE_IP, IP: 404524 PERF_SAMPLE_WEIGHT, Weight: 77 PERF_SAMPLE_DATA_SRC, Raw: 68100842 Load Hit L3 cache No snoop Hit Level 1 TLB Level 2 TLB I've looked into your code in order to compare it with the perf tool and it looks like you support it in the code in the following lines of lib/parse_record.c, so it looks that sample_type is not tagged with PERF_SAMPLE_ADDR bit. 511 if (sample_type & PERF_SAMPLE_ADDR) { 512 long long addr; 513 memcpy(&addr,&data[offset],sizeof(long long)); 514 if (!quiet) printf("\tPERF_SAMPLE_ADDR, addr: %llx\n",addr); 515 offset+=8; 516 } I tweaked a bit the perf dump application so that it prints the sample_type and it always shows c10f whereas your binary prints c001. If I simply go to one of the tests (say sample_data_src.c) and force pe.sample = 0xc10f then it works (printing additional data). So, would the following change make sense into your code to emit the sampled address? Best regards. WARNING / LEGAL TEXT: This message is intended only for the use of the individual or entity to which it is addressed and may contain information which is privileged, confidential, proprietary, or exempt from disclosure under applicable law. If you are not the intended recipient or the person responsible for delivering the message to the intended recipient, you are strictly prohibited from disclosing, distributing, copying, or in any way using this message. If you have received this communication in error, please notify the sender and destroy and delete any copies you may have received. http://www.bsc.es/disclaimer [-- Attachment #2: sample_data_src.c.patch --] [-- Type: text/x-patch, Size: 531 bytes --] diff --git a/tests/record_sample/sample_data_src.c b/tests/record_sample/sample_data_src.c index 1c3d260..35c7e81 100644 --- a/tests/record_sample/sample_data_src.c +++ b/tests/record_sample/sample_data_src.c @@ -113,7 +113,7 @@ int main(int argc, char **argv) { pe.size=sizeof(struct perf_event_attr); pe.sample_period=SAMPLE_FREQUENCY; pe.sample_type=PERF_SAMPLE_IP | PERF_SAMPLE_WEIGHT | - PERF_SAMPLE_DATA_SRC; + PERF_SAMPLE_DATA_SRC | PERF_SAMPLE_ADDR ; global_sample_type=pe.sample_type; ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: About using PEBS from the user space 2015-05-03 22:19 ` Vince Weaver 2015-05-04 8:13 ` Harald Servat 2015-05-04 10:17 ` Harald Servat @ 2015-06-25 16:00 ` Harald Servat 2015-06-25 19:06 ` Manuel Selva 2 siblings, 1 reply; 7+ messages in thread From: Harald Servat @ 2015-06-25 16:00 UTC (permalink / raw) To: Vince Weaver; +Cc: linux-perf-users On 04/05/15 00:19, Vince Weaver wrote: > On Mon, 4 May 2015, Harald Servat wrote: > >> Dear list, >> >> I'd like to use the perf library to access PEBS so as to collect referenced >> memory addresses from the user space. I think I've successfully setup the perf >> structures (struct perf_event_attr) to configure the performance counters, but >> I don't see what should I do to access to the captured memory addresses. I've >> seen that within arch/x86/kernel/cpu/perf_event_intel_ds.c there are the >> routines alloc_pebs_buffer, alloc_ds_buffer which seems to allocate and setup >> the necessary buffers using kmalloc_node calls. Question is, how can replicate >> this from the user space? And how we should connect these buffers to the PEBS >> infrastructure using perf calls? > > You can try looking at the example code in my perf_event_tests code. > https://github.com/deater/perf_event_tests > > The stuff you are looking for is probably covered in the > test/record_sample/samples_data_src > test/record_sample/sample_weight > and especially the > test/record_sample/sample_regs_intr > tests, although that last one requires a fairly recent kernel to work. > > Vince Hello, is there a way to setup PEBS to collect information from loads that take at least X cycles to complete using MSR_PEBS_LD_LAT_THRESHOLD through this approach? Thank you! WARNING / LEGAL TEXT: This message is intended only for the use of the individual or entity to which it is addressed and may contain information which is privileged, confidential, proprietary, or exempt from disclosure under applicable law. If you are not the intended recipient or the person responsible for delivering the message to the intended recipient, you are strictly prohibited from disclosing, distributing, copying, or in any way using this message. If you have received this communication in error, please notify the sender and destroy and delete any copies you may have received. http://www.bsc.es/disclaimer ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: About using PEBS from the user space 2015-06-25 16:00 ` Harald Servat @ 2015-06-25 19:06 ` Manuel Selva 2015-06-26 8:13 ` Harald Servat 0 siblings, 1 reply; 7+ messages in thread From: Manuel Selva @ 2015-06-25 19:06 UTC (permalink / raw) To: Harald Servat, Vince Weaver; +Cc: linux-perf-users Hello Harald, Setting the config1 field of the perf_event_attr field (as done by the perf mem record tool) to X will instruct the PMU to only sample loads with latency higher than X. Is it what you are looking for ? ---- Manu On 06/25/2015 06:00 PM, Harald Servat wrote: > On 04/05/15 00:19, Vince Weaver wrote: >> On Mon, 4 May 2015, Harald Servat wrote: >> >>> Dear list, >>> >>> I'd like to use the perf library to access PEBS so as to collect >>> referenced >>> memory addresses from the user space. I think I've successfully setup >>> the perf >>> structures (struct perf_event_attr) to configure the performance >>> counters, but >>> I don't see what should I do to access to the captured memory >>> addresses. I've >>> seen that within arch/x86/kernel/cpu/perf_event_intel_ds.c there are the >>> routines alloc_pebs_buffer, alloc_ds_buffer which seems to allocate >>> and setup >>> the necessary buffers using kmalloc_node calls. Question is, how can >>> replicate >>> this from the user space? And how we should connect these buffers to >>> the PEBS >>> infrastructure using perf calls? >> >> You can try looking at the example code in my perf_event_tests code. >> https://github.com/deater/perf_event_tests >> >> The stuff you are looking for is probably covered in the >> test/record_sample/samples_data_src >> test/record_sample/sample_weight >> and especially the >> test/record_sample/sample_regs_intr >> tests, although that last one requires a fairly recent kernel to work. >> >> Vince > > Hello, > > is there a way to setup PEBS to collect information from loads that > take at least X cycles to complete using MSR_PEBS_LD_LAT_THRESHOLD > through this approach? > > Thank you! > > WARNING / LEGAL TEXT: This message is intended only for the use of the > individual or entity to which it is addressed and may contain > information which is privileged, confidential, proprietary, or exempt > from disclosure under applicable law. If you are not the intended > recipient or the person responsible for delivering the message to the > intended recipient, you are strictly prohibited from disclosing, > distributing, copying, or in any way using this message. If you have > received this communication in error, please notify the sender and > destroy and delete any copies you may have received. > > http://www.bsc.es/disclaimer > -- > To unsubscribe from this list: send the line "unsubscribe > linux-perf-users" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: About using PEBS from the user space 2015-06-25 19:06 ` Manuel Selva @ 2015-06-26 8:13 ` Harald Servat 0 siblings, 0 replies; 7+ messages in thread From: Harald Servat @ 2015-06-26 8:13 UTC (permalink / raw) To: Manuel Selva, Vince Weaver; +Cc: linux-perf-users Ah! Great, thank you Manuel!! On 25/06/15 21:06, Manuel Selva wrote: > Hello Harald, > > Setting the config1 field of the perf_event_attr field (as done by the > perf mem record tool) to X will instruct the PMU to only sample loads > with latency higher than X. Is it what you are looking for ? > > ---- > Manu > > On 06/25/2015 06:00 PM, Harald Servat wrote: >> On 04/05/15 00:19, Vince Weaver wrote: >>> On Mon, 4 May 2015, Harald Servat wrote: >>> >>>> Dear list, >>>> >>>> I'd like to use the perf library to access PEBS so as to collect >>>> referenced >>>> memory addresses from the user space. I think I've successfully setup >>>> the perf >>>> structures (struct perf_event_attr) to configure the performance >>>> counters, but >>>> I don't see what should I do to access to the captured memory >>>> addresses. I've >>>> seen that within arch/x86/kernel/cpu/perf_event_intel_ds.c there are >>>> the >>>> routines alloc_pebs_buffer, alloc_ds_buffer which seems to allocate >>>> and setup >>>> the necessary buffers using kmalloc_node calls. Question is, how can >>>> replicate >>>> this from the user space? And how we should connect these buffers to >>>> the PEBS >>>> infrastructure using perf calls? >>> >>> You can try looking at the example code in my perf_event_tests code. >>> https://github.com/deater/perf_event_tests >>> >>> The stuff you are looking for is probably covered in the >>> test/record_sample/samples_data_src >>> test/record_sample/sample_weight >>> and especially the >>> test/record_sample/sample_regs_intr >>> tests, although that last one requires a fairly recent kernel to work. >>> >>> Vince >> >> Hello, >> >> is there a way to setup PEBS to collect information from loads that >> take at least X cycles to complete using MSR_PEBS_LD_LAT_THRESHOLD >> through this approach? >> >> Thank you! >> >> WARNING / LEGAL TEXT: This message is intended only for the use of the >> individual or entity to which it is addressed and may contain >> information which is privileged, confidential, proprietary, or exempt >> from disclosure under applicable law. If you are not the intended >> recipient or the person responsible for delivering the message to the >> intended recipient, you are strictly prohibited from disclosing, >> distributing, copying, or in any way using this message. If you have >> received this communication in error, please notify the sender and >> destroy and delete any copies you may have received. >> >> http://www.bsc.es/disclaimer >> -- >> To unsubscribe from this list: send the line "unsubscribe >> linux-perf-users" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> WARNING / LEGAL TEXT: This message is intended only for the use of the individual or entity to which it is addressed and may contain information which is privileged, confidential, proprietary, or exempt from disclosure under applicable law. If you are not the intended recipient or the person responsible for delivering the message to the intended recipient, you are strictly prohibited from disclosing, distributing, copying, or in any way using this message. If you have received this communication in error, please notify the sender and destroy and delete any copies you may have received. http://www.bsc.es/disclaimer ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2015-06-26 8:13 UTC | newest] Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2015-05-03 22:05 About using PEBS from the user space Harald Servat 2015-05-03 22:19 ` Vince Weaver 2015-05-04 8:13 ` Harald Servat 2015-05-04 10:17 ` Harald Servat 2015-06-25 16:00 ` Harald Servat 2015-06-25 19:06 ` Manuel Selva 2015-06-26 8:13 ` Harald Servat
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